150 PROCEEDINGS OF THE ACADEMY OF 



representatives of the family, except the number of branchial apertures ; in 

 which respect the genus resembles Notida?ius or Heptranchias. That genus 

 has also the " teeth in several rows ; those of the lower jaw flattened, arched, 

 serrated ; those of the upper jaw of diverse forms, the middle ones slender, 

 the outer ones approximating those of the lower jaw in fcrm;" the "snout 

 broad, depressed ;" "spiracles two," the invariable number when developed 

 in all fishes! and " the tail much elongated, with the fin beneath." Noto- 

 rhynchus is therefore not distinguished by any character whatever from Hep- 

 tranchias, either in the generic or specific descriptions of Ayres. 



Such being the case, Girard and myself referred the species to the genus 

 Heptanchus or Heptranchius, Raf., and the justness of that reference, under 

 the circumstances, will be unhesitatingly admitted by every logical mind. 



The causes of Dr. Ayres' manifold errors in the case are unknown ; the 

 peculiarity of the dentition of the Notidanoids is described in every text-book 

 of ichthyology, and if Dr. Ayres had even consulted the Animal Kingdom, 

 of Cuvier, accessible to English students through a number of translations, 

 his error would not have been committed. 



Subsequently, I discovered the jaws of a Notidauoid taken at Nisqually, 

 Oregon, by one of the gentlemen attached to Wilke's Exploring Expedition. 

 Finding that the teeth were generically similar to those of Heptanchus indicus 

 of Mailer and Henle, and resembled them rather than those of the typical 

 Heptanchi or Hexanchi, and, further, that the teeth of both more nearly re- 

 sembled those of Hexanchus than Heptanchus, I felt compelled to combine the 

 two species in a peculiar genus. I thus connected the views of Muller and 

 Henle and others regarding the generic value of the number of branchial 

 apertures with those of Bonaparte as to the generic value of the dentition. 

 As the Heptanchus indicus was known to be "dark bluish grey above, with 

 numerous small, irregular, black blotches, lighter beneath," the coloration 

 attributed by Ayres to his Notorhynchus maculatus, I ventured to refer the 

 jaws of the Nisqually shark to that species, since color is generally coinci- 

 dent with structure ; the limited number of species of Notidanoids, the absence, 

 so far as known, of two closely-related representatives in a single Fauna, and 

 the occurrence of Ayres' species in the same faunal region as the Nisqually 

 shark, appeared to warrant this identification, the necessity of confirmation 

 of which, however, I did then, as I now do, emphatically insist upon. I 

 therefore perfectly agree with Dr. Ayres as to the impossibility of certainty 

 " when [his] description is so extremely indefinite," and, in order that 

 further cavil at the identification of the Nisqually shark with Notorhynchus 

 maculatus may be avoided, suggest that the former may be named Notorhynchus 

 borealis. 



Having previously identified the Nisqually shark with the Californian 

 Notidanoid erroneously it may be I felt compelled to retain Ayres' name, 

 and did not detail the history of the genus, as such would have involved the ne- 

 cessity of criticism, but simply remarked that the name "was proposed by Dr. 

 Ayres under a misapprehension." 



Immediately after the publication of my article, Dr. Ayres* insinuated 

 that his name was not given under a misapprehension, and asserted that 

 his "' misapprehension' was, that (he) regarded the species as the type of 

 anew genus. ' ' Such misapprehension is of course evident, but I cannot perceive 

 why the name should be considered apart from the idea of the genus. I in- 

 deed think that the name itself, considered in the abstract, is objectionable 

 and rather unmeaning if not, indeed, more censurable. The etymology of 

 the name is not obvious; its formation would indicate that it meant " back 

 snout, or beak," but it is possible that it is composed of vsflo? and pvyxS, in 

 allusion to the protuberant snout. 



* Proc. California Acad. Nat. Sciences, iii. p. 15. 



TMay, 



