The anatomy and histology of the human eye.

Mode of access: Internet.

Special anatomy and histology /

First ed., 1826; first five eds. issued under title: A treatise on special and general anatomy.

Special anatomy and histology.

First edition, 1826; first five editions issued under title: A treatise on special and general anatomy.

Special anatomy and histology /

Works on medicine ... published by Lea & Blanchard: v. 1 [8] p., at end.

Interactions between ecology, demography, capture stress, and profiles of corticosterone and glucose in a free-living population of Australian freshwater crocodiles

In this study we examined three aspects pertaining to adrenocortical responsiveness in free-ranging Australian freshwater crocodiles (Crocodylus johnstoni). First, we examined the ability of freshwater crocodiles to produce corticosterone in response to a typical capture-stress protocol. A second objective addressed the relationship between capture stress, plasma glucose and corticosterone. Next we examined if variation in basal and capture-stress-induced levels of plasma corticosterone was linked to ecological or demographic factors for individuals in this free-ranging population. Blood samples obtained on three field trips were taken from a cross-sectional sample of the population. Crocodiles were bled once during four time categories at 0, 0. 5, 6, and 10 h post-capture. Plasma corticosterone increased significantly with time post-capture. Plasma glucose also significantly increased with duration of capture-stress and exhibited a positive and significant relationship with plasma corticosterone. Significant variation in basal or stress induced levels of corticosterone in crocodiles was not associated with any ecological or demographic factors including sex, age class or the year of capture that the crocodiles were sampled from. However, three immature males had basal levels of plasma corticosterone greater than 2 standard deviations above the mean. While crocodiles exhibited a pronounced, adrenocortical and hyperglycaemic response to capture stress, limited variation in adrenocortical responsiveness due to ecological and demographic factors was not evident. This feature could arise in part because this population was sampled during a period of environmental benigness. (C) 2003 Elsevier Science (USA). All rights reserved.

Large size in an island-dwelling bird: intraspecific competition and the Dominance Hypothesis

Differences between island- and mainland-dwelling forms provide several classic ecological puzzles. Why, for instance, are island-dwelling passerine birds consistently larger than their mainland counterparts? We examine the 'Dominance hypothesis', based on intraspecific competition, which states that large size in island passerines evolves through selection for success in agonistic encounters. We use the Heron Island population of Capricorn silvereyes (Zosterops lateralis chlorocephalus), a large-bodied island-dwelling race of white-eye (Zosteropidae), to test three assumptions of this hypothesis; that (i) large size is positively associated with high fitness, (ii) large size is associated with dominance, and (iii) the relationship between size and dominance is particularly pronounced under extreme intraspecific competition. Our results supported the first two of these assumptions, but provided mixed evidence on the third. On balance, we suggest that the Dominance Hypothesis is a plausible mechanism for the evolution of large size of island passerines, but urge further empirical tests on the role of intraspecific competition on oceanic islands versus that on mainlands.

Anatomy of a hemiramphid pharyngeal mill with reference to arrhamphus sclerolepis krefftii (steindachner) (teleostei: hemiramphidae)

The structure and function of the pharyngeal jaw apparatus (PJA) and postpharyngeal alimentary tract of Arrhamphus sclerolepis krefftii, an herbivorous hemiramphid, were investigated by dissection, light and scanning electron microscopy, and X-ray analysis of live specimens. A simple model of PJA operation is proposed, consisting of an adductive power stroke of the third pharyngobranchial that draws it posteriorly while the fifth ceratobranchial is adducted, and a return stroke in which the third pharyngobranchial bone is drawn anteriorly during abduction of the fifth ceratobranchial. Teeth in the posteromedial region of the PJA are eroded into an occlusion zone where the teeth of the third pharyngobranchial are spatulate incisiform and face posteriorly in opposition to the rostrally oriented spatulate incisiform teeth in the wear zone of the fifth ceratobranchial. The shape of the teeth and their pedestals (bone of attachment) is consistent with the model and with the forces likely to operate on the elements of the PJA during mastication. The role of pharyngeal tooth replacement in maintaining the occlusal surfaces in the PJA during growth is described. The postpharyngeal alimentary tract of A. sclerolepis krefftii comprises a stomachless cylinder that attenuates gradually as it passes straight to the anus, interrupted only by a rectal valve. The ratio of gut length to standard length is about 0.5. Despite superficial similarities to the cichlid PJA (Stiassny and Jensen [1987] Bull Mus Comp Zool 151: 269-319), the hemiramphid PJA differs in the fusion of the third pharyngobranchial bones, teeth in the second pharyngobranchials and the fifth ceratobranchial face anteriorly, the presence of a slide-like diarthroses between the heads of the fourth epibranchials and the third pharyngobranchial, the occlusion zone of constantly wearing teeth, and the unusual form of the muscularis craniopharyngobranchialis. The functional relationship between these structures is explained and the consequence for the fish of a complex PJA and a simple gut is discussed. (C) 2002 Wiley-Liss, Inc.

Anatomy of the pharyngeal jaw apparatus of Zenarchopterus (Gill) (Teleostei : Beloniformes)

The structure of the pharyngeal jaw apparatus (PJA) of Zenarchopterus dispar and Z. buffonis, carnivorous estuarine and freshwater West-Pacific halfbeaks, was investigated using dissection, light, and scanning electron microscopy as part of a comparison with estuarine and marine herbivorous confamilials. The Zenarchopterus PJA differs from published descriptions of hemiramphid PJAs in that the otic capsules are less pronounced; the pharyngocranial articulation facet is trough-like; the third pharyngobranchials are ankylosed; the second pharyngobranchial anterior processes are relatively hypotrophied; all pharyngeal teeth except the posterior teeth in the fifth ceratobranchial face posteriorly; the muscularis craniopharyngobranchialis 2 posterior is short; the muscularis craniopharyngobranchialis 2 anterior is lacking, as is its insertion site, the inferior parasphenoid apophysis; the protractor pectoralis is well developed; the pharyngocleithralis internus originates dorsal to the level of the fifth ceratobranchial bony process; the fifth ceratobranchial bony processes are directed ventrolaterally; the opposing upper and lower tooth fields appear not to occlude erosively; and the muscular portion of the pharyngohyoideus is well developed anteriorly. The extent of these differences and their implications for the function of the PJA support recent molecular studies that suggest that the Hemiramphidae is polyphyletic. (C) 2004 Wiley-Liss, Inc.

Reproductive anatomy of the strictly monogamous Capricorn silvereye Zosterops lateralis chlorocephalus

Anatomy of male and female comparable with similar-sized species that show low rates of extra-pair-paternity, hence low sperm competition.

Branchial vascular pathways in two species of Tetraodontiformes and the concept of secondary vessels and nutrient arteries

The vascular organisation of the branchial basket was examined in two Tetraodontiform fishes; the three-barred porcupinefish, Dicotylichthys punctulatus and the banded toadfish, Marylina pleurosticta by scanning electron microscopy of vascular casts and standard histological approaches. In D. punctulatus, interarterial anastomoses (iaas) originated at high densities from the efferent filamental and branchial arteries, subsequently re-anastomosing to form progressively larger secondary vessels. Small branches of this system entered the filament body, where it was interspersed between the intrafilamental vessels. Large-bore secondary vessels ran parallel with the efferent branchial arteries, and were found to constitute an additional arterio-arterial pathway, in that these vessels exited the branchial basket in company with the mandibular, the carotid and the afferent and efferent branchial arteries, from where they gave rise to capillary beds after exit. Secondary vessels were not found to supply filament muscle; rather these tissues were supplied by single specialised vessels running in parallel between the efferent and afferent branchial arteries in both species examined. Although the branchial vascular anatomy was generally fairly similar for the two species examined, iaas were not found to originate from any branchial component in the banded toadfish, M. pleurosticta, which instead showed a moderate frequency of iaas on other vessels in the cephalic region. It is proposed that four independent vascular pathways may be present within the teleostean gill filament, the conventional arterio-arterial pathway across the respiratory lamellae; an arterio-arterial system of secondary vessels supplying the filament and non-branchial tissues; a system of vessels supplying the filament musculature; and the intrafilamental vessels (central venous sinus). The present study demonstrates that phylogenetic differences in the arrangement of the branchial vascular system occur between species of the same taxon.

Structure and ultrastructure of the silk glands and spinneret of Helicoverpa armigera (Hubner) (Lepidoptera : Noctuidae)

This study provides comprehensive documentation of silk production in the pest moth Helicoverpa armigera from gland secretion to extrusion of silk thread. The structure of the silk glands, accessory structures and extrusion apparatus are reported. The general schema of the paired silk glands follows that found for Lepidoptera. Morphology of the duct, silk press, muscle attachments and spigot are presented as a three-dimensional reconstruction and the cuticular crescent-shaped profile of the silk press is demonstrated in both open and closed forms with attendant muscle blocks, allowing advances in our knowledge of how the silk press functions to regulate the extrusion of silk. Growth of the spigot across instars is documented showing a distinctive developmental pattern for this extrusion device. Its shape and structure are related to use and load-bearing activity. (c) 2005 Elsevier Ltd. All rights reserved.