342 U. 8. p. R. R. EXP. AND SURVEYS ZOOLOGY — GENERAL REPORT. 



{Cyclopterus), exhibit traits of a kindred nature. In most of the minnows {Cyprinodontidae) 

 and the Anahleps, the eggs hatch within the abdomen of the female, and in the Embiotocoids 

 there is a special pouch witliin which the eggs are first formed and afterwards develop until the 

 young have undergone their fullest metamorphoses. The Embiotocoids, when observed for the 

 first time, seemingly recalled to mind the opossum of North America, and the entire tribe ot 

 the kangaroo of Australia ; bi'.t if any fish deserves the appellation of opossum-fish we venture 

 to claim it for the tribes of LophobrancJdi we are treating of in these pages. 



The Lophohranchii have been recently the subject of investigations on the part of Mr. Kaup. 

 The genera which he has establislied being for the present known to us only nominatively, we 

 are at a loss to distribute them in the families we are inclined to adopt in the present Order. 

 The generic divisions adopted by Mr. Dumeril in his " Ichthyologie analytique" are not 

 sufficiently characterised to the same purpose. 



Family llIPPOCAMriDAE, Owen. 



The " sea-horse" family being composed, to our knowledge, of but one genus {Hippocampus), 

 ■we will not enlarge upon its characters here, since alluding to them would be a mere repetition 

 of their enumeration further on. 



SYS.—IIippocamptdae, Owen, Led. Comp. Anat. Vertebr. Anim. 18-16, 50.— lio. Iconogr. Eiicycl. II, 1850, 232. 



This family is not adopted by all systematic writers, some of whom combining it with that of 

 Synrjnathidae, either under the latter appellation, else designating it by the name of the Order 

 itself. The position these fishes assume in the media in wliich they live is not the least of their 

 peculiarities entitling them to the rank of a family in the ichthyic method. 



rilFPOJAMPUS, Cuv. 



Gen. Char. — Body short, deep, and compressed lieptangular ; tail slender, quadrangular, tapering, and coiled up inwardly. 

 External surface of both body and tail divided into parallelograms by longitudinal and transverse ridges, with tubercular points 

 at the angles of intersection. Head sub-pyramidal, bent downwards. One dorsal fin; neither caudal nor ventrals ; an anal 

 fin in hoth sexes. Pectoral fins of moderate development. 



Syh. —Hyppocampus, Gov. R6gn. Anim. II, 1817, 157 ; 2d cd, II, 1829 ; &, ed. illustr. I'oiss. 331.— Storer, Rop. Fish. 

 Mass. 1839, 1G7 ; &, Synops. 184G, 239.— DeKay, New Y. Faun. IV, 1842, 322.— Dcm. Ichthyol. analyt. 

 18.56, 170. 



Deprived of caudal fin to execute their onwards motion, the sea-horses (Hippocampus) are 

 reduced to coiling up their tail and to assume a vertical position in the medium in which they 

 live, a position unknown elsewhere in the class of fish. They progress slowly and uniformly 

 forwards or obliquely upwards ; in their descending movements the orientation is not changed ; 

 the tail remains directed downwards. The movements are executed by the means of the pec- 

 toral fins ; the dorsal acting chiefly as a rudder. They appear to be easily tired, for afcer 

 being active a short time they seek submarine supports to which they attach themselves by the 

 means of their prehensile tail, 



HIPPOCAMPUS INGENS, Grd. 



The Great Calirornia Sea>Horse. 



Spec Char— Body composed of twelve segments; tail longo- than the body and head together, divided into thirty-eight 

 segments. Head constituting the sixth of the total length; it being conluincd about twice in the length of the body and thrice in 

 that of the tail. Spiny crest at the base of the snout rather inconspicuous. Throe pairs only of thoracic bony processes. Blackish 

 or deep chesnut brown, punctulated with white. 



