12 Dr. C. F. Liitken on the Changes of Form in Fishes 



Cyhium Solandri, C. & Y.,C.petus^ Poej, the type of the genus 

 Acanthocybium^ Gill, and recently described by M. Doderleia 

 under the name of C. Verany. This genus is clearly distin- 

 guished from the true Cyhium : — 1, by the long and pointed 

 form of the head, in which the mandible is longer than the 

 upper jaw, the cleft of the mouth reaches only to beneath the 

 eye, and the posterior part of the maxillary is not visible but 

 concealed by the suborbital plate ; the jaws are armed with a 

 close series of cutting-teeth lancet-shaped and finely crenu- 

 lated ; 2, by the branchiae, which exactly resemble those of 

 XiphiaSj their leaves being soldered together in the form of a 

 network 5 3, by the distance between the points of the caudal 

 fin, which scarcely exceeds the length of the head, &c. That 

 Acantliocyhium is theThynnoid form most nearly approaching 

 the swordfish is shown by the peculiar modification of the 

 branchiae and the prolongation of the intermaxillaries, which, 

 if more developed, would become the short rostrum of Tetrap- 

 turus helone. This genus thus acquires peculiar importance 

 from a systematic point of view ; and a detailed investigation 

 of the still unknown structure of its skeleton would be espe- 

 cially desirable, 



I have regarded as belonging to Orcynus germo some small 

 Thynuoids of 8-17 millims. long, fished in the open sea. 

 The corselet and the keels of the tail are wanting ; the finlets 

 are only just indicated in the largest specimen, and are not 

 distinct ; there is no trace of them in the others, which 

 are distinctly lieterocercal and perfectly colourless, with the 

 exception of the eyes and the first dorsal, which are black. 

 The prgeoperculum is armed with spines in all. 



7. COKYPHiENA EQUISETIS, L., C. HIPPUEUS, L., and 

 C. FASCIOLATA, Pall. 



The genus Coryphcena (the " dolphins," as our sailors call 

 them) is one of those which have tlie pelagic character most 

 strongly marked ; at the same time it furnishes an example 

 instar omnium of the extreme confusion that has resulted from 

 the circumstance that a really very limited number of exist- 

 ing species has been broken up into a great number of nominal 

 species which are based only upon differences of age and sex, 

 upon individual peculiarities, diiferent geographical localities, 

 incorrect drawings, imperfect descriptions, &c., a confusion 

 for which, however, George Cuvier has been wrongly made 

 personally responsible. The error committed in dividing the 

 species into two genera, Coryphcena and Lampugas, has 

 already been rectified by a competent authority ; and the 

 number of species reputed well established has, at the same 



