4 R. COLLETT. 
The dentition is also remarkable, and in this respect it does not 
resemble any present kind of shark. The teeth are arranged in separate 
rows which lie transversely in the jaws, each tooth forming three 
equally long points directed backwards, fine as needles, and there are 
five such teeth in each of the forty to fifty rows of which the 
dentition consists. 
The great interest attached to this species, and which makes it 
one of the most remarkable of living fish, consists in its connections, 
it not being closely related to any present variety of shark, or to 
any that have become extinct in later periods of the Earth’s existence, 
but whose ancestors belonged to the oldest paleeozoic formation — 
the Devonian — when there lived forms of sharks whose teeth were 
comparatively of the same nature as those of the present specimen. 
No known vertebrate has thus its nearest kindred so far back 
towards the dawn of organic existence. In other words, Chlamydose- 
lachus is ,the oldest of all living types of vertebrata‘. 
In 1884, Chlamydoselachus anguineus, was first described by 
Dr. Garman (Bull. Essex Instit., Salem Jan. 1884) from a large, but 
imperfect female individual, which was purchased in a miscellaneous 
lot of alcoholic specimens by the Museum of Comparative Zoology 
at Harvard College (Cambridge, Mass.) from Professor H. A. Ward, 
who had secured it in Japan| The specimen was not in a good state 
of preservation, most of the viscera being absent, and the end of the 
tail wanting. Its total length may be estimated at about 1580 mm.? 
Dr. Garman’s preliminary description of the species, which is 
comparatively lengthy, concludes with the following words: 
ylhere is a certain embryonic look about the species, as others 
who have seen it also remark, that calls for a comparison with fossil 
representatives of the Selachians. Among them I have been unable 
1 As stated later on (p. 7) the species had been discovered in Japan a few 
years previously, and forwarded to Dr. Déderlein of Strassburg, who, so early 
as 1882, wrote an account of the fish, which was not, however, ever published. 
2 The length is stated to have been 59.5 inches, to which must be added the 
end of the tail which was wanting, which end was, probably, of a length of 
about 2 inches, this giving a total length of some 611/2 English inches, 
