ZOOLOGY. 625 



have a better cbauce to trace the affiuities." Mr. Garnian was finally 

 iuclined to consider the species as the type, not only of a new genus 

 and family but even of " a new order, to which the name Selachoph- 

 ichthyoidi might be given, and which stands nearer the true fishes 

 than do the sharks proper." 



The new shark was 5 feet long and less than 4 inches in greatest 

 diameter. It was obtained in Japan. 



Next, P.rofessor Cope, soon afterwards, in a communication to Science, 

 expressed the opinion that the newly described shark was congeneric 

 with the Diplocli(S or Didymodus of the Devonian epoch, and that there- 

 fore it was the oldest living type of Vertebrata. 



In a subsequent number of Science, Professor Gill commented upon 

 the views already expressed and had to difl'er from both gentlemen. 

 He was disposed to agree with Mr. Garman in the conclusion that 

 Chlamydoselachus angnineus approached nearer the true fishes than 

 do the sharks proper, not because it appeared to be in the line of des- 

 cent between the two, but because it was nearer the primitive line 

 from which both types have diverged. It is doubtful, however, wliether 

 it is a more primitive type than the Notidanids. As to its relations to 

 extinct types, however, he dissented from both Mr. Garman and Pro- 

 fessor Cope, and doubted whether it was closely related to any known 

 extinct forms, urging that both of the forms to which it had been ap- 

 proximated hj Messrs. Garman and Cope were very widely separate. 

 The Cladodus and its relatives were at least subordinally distinct, and 

 Biplodus or Didymodus (which, he showed, should be called Pleur acan- 

 thus) appeared to have had no relations whatever to it, and apparently 

 did not belong to the same order or even subclass. On the whole 

 Chlamydoselachus appeared to him to be quite clearly related to the 

 Notidanids, but in a revised natural system of the Squali, the two 

 families might be considered as representatives (and the only known 

 representatives) of distinct suborders — the Notidanids of the suborder 

 Opistharthri, and the Chlamydoselachids of the suborder Pternodonta 

 or Selachophichthyoidei. The two seem to be closely related, however. 

 {Science, v. 3, pp. 110-117 {Garman); v. 3, p. 275 {Cope); v. 3, pp. 345- 

 346 {Garman, Gill) ; V. 4, p. 484 ; {Garman) V. 4, p. — {Gill}; Bull. Essex 

 Inst, V. 16.) 



Teleostomes or fishes. 



The lateral line of Fishes. — The so-called lateral line of fishes and its 

 extension on the head has been a subject of many investigations. One of 

 the latest published on the subject is by M. Paul De S6de, who has paid 

 special attention to the histology and development thereof. We cannot 

 enter upon the anatomical details and must remain content to briefly 

 consider the results of some of the experiments made by the author. 

 He had undertaken the vivisection of certain fishes, subjecting them to 

 aufesthesia and then experimented upon them in several ways. He 

 chiefly emi)loyed chloroform, and placed the fish in a glass jar three- 

 S, Mis. 33 40 



