THE ANATOMY OF THE FRILLED SHARK 

 CHLAMTDOSELACHUS AKGUIKEUS Garman 



By Bertram G. Smith 



Professor of Anatomy 



New York University College of Medicine 



INTRODUCTION 



Interest in Chlamydoselachus centers around the problem of its affinities. It has been 

 said (Garman, 1884.1, .2) to have "a certain embryonic look." It has been called a living 

 fossil. It has been designated (Garman, 1884.3, .4; Gill, 1884.1,. 2) the oldest living type 

 of vertebrate. More conservatively, Woodward (1921, p. 37) regards Chlamydoselachus 

 as one of the most primitive of the true Selachii. On the other hand, a study of the 

 external characters alone (Gudger and Smith, 1933) is sufficient to indicate that Chlamy- 

 doselachus possesses many structural adaptations of a very special nature. In the present 

 article I have endeavored to distinguish those features that represent a high degree of 

 differentiation, from others that link Chlamydoselachus with the most primitive fishes. 



Since the publication of Garman's (1885.2) description of a partly eviscerated speci' 

 men with a slightly mutilated tail, there has been no comprehensive account of the 

 anatomy of Chlamydoselachus; but there have been many investigations dealing with 

 particular organs or parts of the body of this rare fish. Some of these contributions were 

 published in such form as to be readily accessible, but much information concerning the 

 structure of Chlamydoselachus lies buried under titles of a somewhat general nature. 

 In bringing together a digest of all these records I have endeavored to supplement them, 

 wherever it seemed desirable and practicable, by original observations on all the ma- 

 terial available. 



This material includes three large female specimens (lengths 1350 mm., 1485 mm. 

 and 1550 mm. respectively) brought from Japan by Dr. Bashford Dean, and now in the 

 collections of the American Museum of Natural History; and a fourth large female 

 specimen (1398 mm. long) kindly lent by Dr. E. Grace White. The first three specimens 

 had been preserved in formalin and alcohol for about thirty years. The fourth shark 

 had been preserved in formalin, then alcohol, for an unknown period. In all the specimens 

 the viscera were in a more or less unsatisfactory condition for study, and from the fourth 

 specimen the digestive organs had been entirely removed. Nevertheless, a careful exami' 



EDITOR'S NOTE: — The first study of the anatomy of Chlamydoselachus was made by Samuel Garman at the Museum of Com- 

 parative Zoology, Cambridge, Mass., on the first specimen ever brought to America (1884). Carman's monograph was published in 

 1885 and is referred to herein as 1885.2 The original drawings and the woodcuts made from these have fortunately been preserved 

 in Cambridge. They have been most kindly sent to me by Dr. Thomas Barbour, Director of the Museum of Comparative Zoology. 

 Many of the woodcuts have become warped and spUt by drying during the past half century, but it is a great satisfaction to be 

 able to use three of them (Text-figures 94, and 101 a-b) in this paper, and to have new cuts made from certain of the original draw- 

 ings — those representing the brain, which are reproduced here as Plate VI. 



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