292 SKETCHES OP BRITISH ICHTHYOLOGY. 



jects above each eye. The operculum exhibits striae radiating from 

 the front. The figure of the body is rendered heptangular by the 

 existence of three angular lines on each side, and a seventh running 

 along the abdomen. The back is flat: the transverse segments of 

 the body are eleven in number. The pectoral fins, small and con- 

 taining about eight rays each, are situated immediately behind the 

 operculum. The dorsal fin consists of about sixteen rays : the anal 

 fin, of four rays, is peculiar to the female. The abdomen measures 

 twice the depth of the tail ; which from the vent assumes a quad- 

 rangular figure, and terminates in a point : the number of its seg- 

 ments is about thirty. The general colour of H. brevirostris is pale 

 ash-brown, with changeable iridescence, and variable tints of blue 

 dispersed over the whole. It has been found on the southern shores 

 of England, at Guernsey and the other Channel islands; and a most 

 interesting account of its habits, communicated by F. C. Lukis, Esq., 

 of Guernsey, appears in Mr. Yarrell's valuable work. It is figured, 

 by Willughby, i. 25, fig. 3 ; by Bonnaterre, pi. 22, fig. 75 ; and by 

 Yarrell, vol. ii., p. 342. The food of the Hippocampus, although 

 not clearly ascertained, is supposed to be the same as that of the 

 different species of the Syngnathus genus. 



It now remains for me only to explain the peculiarities of struc- 

 ture and function to which I have before alluded, as characterizing 

 the males of the different species which belong to the two genera of 

 the Syngjiathidoe, just enumerated and described. First, then, it 

 had long been known that the ova of the female fish were received 

 into the sub-caudal pouch which constitutes a sexual peculiarity in 

 the two species of the first sub-genus of Syngnathus, and there de- 

 veloped ; but these pouches were supposed to exist exclusively in 

 the female : nor does any suspicion to the contrary appear to have 

 entered the mind of Cuvier : for, in his description of the Syngnathi, 

 he makes the following observation : " Leur generation a cela de 

 particulier, que leurs oeufs se glissent et eclosent dans une poche 

 qui se forme par une boursouflure de la peau, dans les uns sous le 

 ventre, dans les autres sous la base de la queue, et qui se fend pour 

 laisser sortir les petits." See Regne Animal, vol. ii., page 362. 



It was reserved for Mr. Walcott, author, I believe, of a Synopsis 

 of British Birds, and of several other works upon Natural History, 

 to discover that the sub-caudal pouch is peculiar to the male fish of 

 Syngnathus acus ; and that the female casts her roe into the false 

 belly of the male, where it is retained, and subsequently developed. 

 This extraordinary fact is supported by the evidence of several con- 

 tinental naturalists ; and Mr. Yarrell has verified it by the unerring 



