1859.] EGERT0X OLD RED FISHES. 123 



Commencing with the family Acanthodei, three new species are 

 added to the genus Chirolepis : — 



Chtrolepis certes. — I am unable to distinguish this species from 

 Chirolepis Cummingice. The characters derived from the head are 

 entirely deceptive. The obliquity of the mouth and large size of the 

 head are owing to the dislocation of the cranial bones ; and the ap- 

 parent shortness of the trunk is attributable to the concealment of 

 the nape by some of these dislocated members, and the mutilation of 

 the extremity of the upper lobe of the tail. The scale-characters 

 coincide with those of Chirolepis Cummingice. 



Chtrolepis macrocephales. — This specimen has had a squeeze, 

 which has thrown down one ramus of the lower jaw, and forced the 

 pectoral arch away from its normal position. If these parts are 

 restored to their proper site, the proportional measurements differ in 

 no respect from those of Chirolepis TrailU. 



Chtrolepis velox. — This is a well-marked species, characterized 

 by its small head, slender form, and large fins. The ventral and 

 anal fins are more approximated than in Cliirolepis TrailU. 



Of the genus Chiracanthus three new species are described, all 

 from the Orkney Flags : — 



Chiracaxthes graxdispines. — This is a good addition to the 

 genus. The specific characters arc strongly marked, and it is alto- 

 gether the finest species of Chiracanthus yet discovered. 



CHiEACAxniEs lateralis. — I am unable to detect any specific 

 details in which this fish differs from Chiracanthus minor. The 

 preservation of the scales pierced for the mucous duct cannot be 

 taken as a specific character. 



Chiracaxthes pelverulentes. — Tkc keen eye of Prof. M'Coy has 

 detected in the minute scales of this specimen a good and substantial 

 specific distinction, well expressed in the term puherulentus. 



The last genus of the Acanthodei, namely Diplacanthus, is aug- 

 mented by two new species : — 



Diplacantiies GiuiiEs. — This species most nearly resembles Dijda- 

 canthus erassiapinus, from which it is easily distinguished by the 

 greater length of the dorsal spines. 



Dii'lacvni lies rKKARMATis. — A very good species, differing re- 

 markably from its nearest congener, Diplaccmthus longispvnua, in the 

 shortness of tin- trunk, and the approximation of the dorsal spines. 

 In the family rffaeSawrodipterida, Prof. M'Coy proposes to sub- 

 stitute Diplopterax for Diplopterus of Agassiz, in consequence of the 

 latter term having been anticipated by Boie. Thai this naturalist 

 should have employed it to designate a genus of Cuckoo is hardh 

 sufficient reason for the change ;' otherwise, in fairness to palaeonto- 

 logists, the ornithologists should lie called upon to revoke .\n</>hi- 

 ptertu and other titles to which they have no claim >>t' priority. 



Din.ori 1.1:1 s (.km hi-. In the absence of other structural pecu- 

 liarities, I cannot accept the slender form of this specimen as a 



specific character. Theamounl of variation in this particular in the 

 old Hed fishes is most remarkable ; ami. without other corroboration, 

 mere measurement cannot he relied upon for a constant character. 



