796 SCIENTIFIC RECORD FOR 1885. 



are better developed than iu Muraenoides, their position is more ante- 

 rior, and a spine and two rays of moderate size exist. ( Proc. U. S. N'at. 

 2fus. V. 8, pp. 192, 192.) 



The American Flying Fishes. — The fishes of the sub-family of Exocce- 

 tines, including the true flying fishes, have been examined recently by 

 Messrs. Jordon and Meek, and it appears that seventeen species refer- 

 able to four genera are recognizable as inhabitants of the American 

 waters on both sides of the continent. Three of these, Fodiator acutus, 

 Farexoccetus mesogaster, and Halocypselus evolans, belong to special 

 genera, while all of the others are members of one natural genus (Exo- 

 coetus). Eight of the Exocoetines have been obtained off the At- 

 lantic coast of the United States and one {Exocoetus Californieus) 

 along the Pacific coast. The California flying fish is one of the largest 

 of the family. {Proc. U. S. J^at. ilfws., v, 8, pp. 67.) 



Amphibians. 



The Retrograde Metamorphosis of Siren. — The remarkable eel-like am- 

 phibian named Siren lacertina, and abundant in the southern parts of 

 the United States, is the type of a group, by some considered as an 

 order, distinguished by some remarkable characteristics ; some of these 

 have been considered to be evidf'nces of degeneration. Professor Cope 

 has now reason to believe that there are also indications to be found of 

 "a retrograde metamorphosis" in the "history of its branchial appara- 

 tus. " He had been at a loss to account for the curious condition fre- 

 quently observed in the branchisB of the sirens. The fringes are fre- 

 quently partially atrophied and "inclosed in a common dermal invest- 

 ment of the branchial ramus, or all the rami are covered by a common 

 investment, so as to be completely fuuctionless and immovable. This 

 character, observed in the Pseudohranchus striatus, gave origin to its 

 separation from the genus Siren." The character is however also ob- 

 servable in the typical species, Siren lacertina, at a certain age, and 

 the real difference, so far as generic valuation is concerned, depends 

 simply on the different number of the digits represented in the two 

 species. 



Professor Cope surprised " on discovering that the fuuctionless con- 

 dition of the branchiae is universal iu young individuals of Siren lacertina 

 of 5 and 6 inches in length ; " and even in a specimen little more 3 inches 

 long they were found " entirely rudimentary and sub-epidermal ; " in 

 fact, according to Professor Cope, only in large adult specimens are the 

 branchiae fully developed. The inference drawn from the facts is, that 

 "the branchiae are in the Sirens not a larval character, as in other pexen- 

 nibrachiate Batrachia, but a character of maturity. Of course, only di- 

 rect observation can show whether Sirens have branchiae on exclusion 

 from the egg ; but it is not probable that they differ so much from the 



