CIILAMYDOSELACIIUS ANGUINEUS. 43 



the Carboniferous and earlier. The excellent work done by James W. 

 Davis, by L. Doderlein, by Fritsch, and by a number of others, in the elu- 

 cidation of the Pleuracanthidae has finally disposed of as non-existent the 

 asserted affinities of ChlamydoseUichus with Cope's Didyniodus, 1884, that 

 is, with Pleuracanthus of Agassiz, 1837. As now separated from the spine- 

 bearing fishrlike Pleuracanths, Xenacanths, with which it should never have 

 been placed, the first suggestion, in 1884, regarding the allies of Chlamy- 

 doselachus is seen to retain its jjertinence ; the affinities are to be looked 

 for away back among the Cladodonts, '•' probably earlier than the Cai'bon- 

 iferous." The idea that the Cladodonts were distinct from the Diplodonts, 

 of the Xenacanthini, the Pleuracanthidae, is well supported by the fossil 

 Cladodont restored by Dean, 1894, under the name " Cladoselache" (see 

 " Fishes, Living and Fossil," 1895, p. 79, fig. 86), from the Cleveland 

 Shales of the Ohio Waverley (Lower Carbon). This form evidently was 

 a true shark with Cladodont dentition and no dorsal spines ; it has no 

 close resemblances to Chlamydoselachus, yet it is sufficiently near to 

 lend support to the theory that the ancestors of the latter had separated 

 from the Diplodonts, the Pleuracanths, and Teleosts at a much earlier 

 date, and to justify search for a Cladodont without dorsal spines, with 

 more than five gill openings, with longer dorsal and anal fins, and with a 

 tail somewhat nearly diphycercal, from which to trace the descent of the 

 ChlamydoselachidiB. 



The name originally applied to the genus was Chlamydoselachus, from 

 X^a.iJ.v<; and creXa^^o?; Giinther's change to Chlamydoselache is not to be 

 countenanced, a-eXdy^r) being the plural form. Similar criticism is to be 

 ai)plied to Selache of Cuvier, 1817 (=Cetorhinus Blainville, 1816), and to 

 Cladoselache of Dean, 1895, generic names which are better written 

 Selachus and Cladoselachus. 



To remark upon one more of the numerous entries in a complete bibli- 

 ography of the genus it may be pointed out that the diagno.ses and descrip- 

 tions occupying pages 22, 23, and 24 of the "Oceanic Ichthyology" by 

 George Brown Goode and Tarleton H. Bean, 1896, are transcribed word for 

 word, without quotation marks, but with changed punctuation, from the 

 article, "An Extraordinary Shark," in vol. XVI., 1884, of the Proceedings 

 of the Essex Institute. It is indeed gratifying to know that the article was 

 so highly appreciated as to demand an expenditure of so much energy as 

 was necessary in making all the changes, yet it is greatly to be regretted 



