Early devonian vertebrates from the Keoydart formation of Nova Scotia.

v.37:no.17(1955)

Comparative direct electrography of the heart of vertebrates

Bibliography: p.44-50.

The fishes of North and Middle America: a descriptive catalogue of the species of fish-like vertebrates found in the waters of North America, north of the Isthmus of Panama /

Mode of access: Internet.

Natural history of vertebrates (except birds); a laboratory and field guide.

Pages 25, 26, 41, 44, 45, 46, 47, 48, 68 and 80 are repeated.

Field notes on vertebrates collected by the Smithsonian-Chrysler East African expedition of 1926,

Proceedings of the United States National Museum, v. 73, no. 17.

A manual of mesostigmatid mites parasitic on vertebrates,

Bibliography: p. 271-316.

Manual of the vertebrates of the northern United States, including the district east of the Mississippi River, and north of North Carolina and Tennessee, exclusive of marine species.

Mode of access: Internet.

Outlines of comparative anatomy of vertebrates /

Includes index.

Sexual endocrinology of non-mammalian vertebrates,

Mode of access: Internet.

A laboratory and field guide to the natural history of vertebrates (except birds) /

"References" included.

Natural history of vertebrates : (except birds) A laboratory and field guide. Rev /

"First edition, copyrighted 1932."

Ancient colour vision: Multiple opsin genes in the ancestral vertebrates

Molecular investigation of the origin of colour vision has discovered five visual pigment (opsin) genes, all of which are expressed in an agnathan (jawless) fish, the lamprey Geotria australis. Lampreys are extant representatives of an ancient group of vertebrates whose origins are thought to date back to at least the early Cambrian, approximately 540 million years ago [1.]. Phylogenetic analysis has identified the visual pigment opsin genes of G. australis as orthologues of the major classes of vertebrate opsin genes. Therefore, multiple opsin genes must have originated very early in vertebrate evolution, prior to the separation of the jawed and jawless vertebrate lineages, and thereby provided the genetic basis for colour vision in all vertebrate species. The southern hemisphere lamprey Geotria australis (Figure 1A,B) possesses a predominantly cone-based visual system designed for photopic (bright light) vision [2. S.P. Collin, I.C. Potter and C.R. Braekevelt, The ocular morphology of the southern hemisphere lamprey Geotria australis Gray, with special reference to optical specializations and the characterisation and phylogeny of photoreceptor types. Brain Behav. Evol. 54 (1999), pp. 96–111.2. and 3.]. Previous work identified multiple cone types suggesting that the potential for colour vision may have been present in the earliest members of this group. In order to trace the molecular evolution and origins of vertebrate colour vision, we have examined the genetic complement of visual pigment opsins in G. australis.

Morphological and physiological specialization for digging in amphisbaenians, an ancient lineage of fossorial vertebrates

Amphisbaenians are legless reptiles that differ significantly from other vertebrate lineages. Most species dig underground galleries of similar diameter to that of the animal. We studied the muscle physiology and morphological attributes of digging effort in the Brazilian amphisbaenid Leposternon microcephalum (Squamata; Amphisbaenia), which burrows by compressing soil against the upper wall of the tunnel by means of upward strokes of the head. The individuals tested (