304 Bashford Dean Memorial Volume 



flexible, the fins (except the pectorals) are set far back, the head is flat, the mouth is sub' 

 terminal and has a wide gape, and the eye v,fith its overhanging brow is decidedly rep' 

 tilian. Thus in many respects the fish has a snake-like appearance. 



The generic term comes from the Greek chlamys, a cloak; and selachus, shark. The 

 allusion here is to the remarkable gill-covers, which as already noted extend from high on 

 the dorsal surface of the head almost all the way across the throat — in the case of the first 

 gill-cover entirely so. Chlamydoselachus is the only shark in which the first gill-covers 

 meet to form a continuous fold across the throat. Long gill-covers are found also in the 

 basking shark, Cetorhinus maximus, but in it the gill-covers, usually called "gill-straps," 

 tend to lie flat as in any ordinary shark, or indeed in any shark other than Chlamydoselachus. 

 As Figures 7 and 16, plates II and V show, what in Cetorhinus or any other shark are 

 straps, here become veritable gill-covers, and so voluminous are they that they are thrown 

 into folds, giving rise to the common name ''fringe-gilled" or "frilled" shark. However, 

 the term "cloak-gill" must be restricted to the first and most voluminous gill-cover, which 

 as noted entirely crosses the throat. 



Despite the fact that Garman (1884.1) had complied with the rules of nomenclature by 

 publishing a figure and description of a specimen of the fish preserved in a great museum, 

 and had given it definite generic and specific names, which as we have seen are accurately 

 descriptive, Gunther (1887), without assigning any reason, changed these to Chlamydo' 

 selache anguinea. However, Garman (1889, p. 43) points out that this new generic name 

 is merely the Greek plural, and that the name should of course be put in the singular, with 

 the specific name in adjectival agreement. Doflein (who has been quoted above) uses 

 Giinther's terminology, probably because he had not seen Garman's papers. 



One other ill-founded attempt to change the name of Chlamydoselachus will be 

 considered later in the section on "Affinities", where its relationship to fossil forms 

 and its place in the system are considered. 



The name originally assigned by Garman stands today, but some curious errors in the 

 spelling have crept into the texts of certain foreign authors. Thus Bolivar (1907) spells the 

 specific name anguinus, and the indexer of the volume in which Bolivar's article appears 

 writes ^^Chlamidoselachus anguineus Garner." Seabra (1913) writes the generic name in 

 two places Chlamydocelachus. Bertrand (1926) makes the same error as Bolivar in writing 

 the specific name, while Maurer's article (1913) prints the specific name anguinens on his 

 plate. All these are undoubtedly mere typographical errors. 



VERNACULAR NAMES 



This fish is so sparingly taken (even in Iberian waters) that, so far as we know, 

 nowhere save in Japan has it any vernacular name. There it is called Rahu\a. We find 

 this vernacular name in Doctor Dean's notes and in some of the systematic works on 

 Japanese fishes. The word means Silk Shark. This name may possibly be given because 

 its fins, especially the anal and the sub-caudal, are thin and delicate in structure and prob- 

 ably have a waving motion in the water. The Japanese call it also To\agizame or Lizard 



