484 PISCES (OSSEI) OSTEODERMI. [SYNGNATHUS, 



ORDER III. OSTEODERMI. 



GEN. 66. SYNGNATHUS, Cuv. 

 * Anal, caudal, and pectoral fins, all present. 



172. S. Acus, Linn. (Great Pipe-Fish.) Body hept- 

 angular anteriorly : crown with an elevated longitudinal 

 ridge ; profile descending in a sinuous curve : snout much 

 narrower, vertically, than the head. 



S. Acus, Linn. Syst. Nat. torn. i. p. 416. Block, Ichth. pi. 91. 

 f. 2. Turt. Brit. Faun. p. 116. Flem. Brit. An. p. 175. Pipe- 

 Fish, Penn. Brit. Zool. vol. Hi. pi. 23. no. 60. lower fig. but not 

 p. 138. Shorter Pipe-Fish, Id. (Edit. 1812.) vol. in. pi. 26. no. 60. 

 lower fig. Low, Faun. Ore. p. 181. 



LENGTH. From twelve to sixteen inches: according to Bloch, from 

 two to three feet. 



DESCRIPT. (Form.) Very much elongated, slender, tapering behind: 

 greatest depth and thickness about equal; each contained thirty-seven 

 times in the entire length : body, from the head to the vent, heptangular ; 

 thence to the termination of the dorsal fin, hexangular ; thence to the 

 caudal, quadrangular : the heptangular portion presents two longitudinal 

 ridges on each side, one on each side of the middle of the back, and one 

 down the middle of the belly; this last terminates at the vent; the 

 dorsal ridges terminate at the end of the dorsal fin, and the upper pair 

 of lateral ridges rise to take their place ; beyond the vent, the under sur- 

 face of the tail is very flat, with the margins rather dilated, and, in the 

 male, contains a long purse-like cavity, for the reception of the ova, 



riing by a longitudinal slit: body protected by transverse, striated, 

 Ids or plates, sixty -three in number ; nineteen occupying that portion 

 of the trunk between the gills and the vent, forty-four the remainder of 

 the length: head compressed, contained (snout included) about seven 

 times and a half in the entire length : occiput rising into a longitudinal 

 elevated ridge, continued over the crown ; the profile falling thence in 

 a sinuous curve to the base of the snout: eyes large, protected above 

 by a sharp osseous ridge ; the intervening space concave ; in front of each 

 a sharp spinous process: snout elongated, nearly twice the length of 

 the rest of the head, compressed, much narrower than the head in a 

 vertical direction; mouth very small, situate quite at the extremity; 

 lower jaw longest, ascending : no teeth : opercle large, marked with 

 diverging striae, closed on all sides by a continuous membrane, the gill- 

 opening being reduced to a small hole on each side of the nape : dorsal 

 so placed as to terminate exactly at the middle point of the entire length ; 

 length of the fin about equal to that of the head ; its height equalling 



