OEDER VI. 



LOPHOBIUNCHII. 



The bony frame or skeleton is but partly ossified in the fishes wliicli compose this Order, and 

 their body is protected by scales or plates partly bony and partly corneous in structure, poly- 

 gonal in shape, articulated and movable one upon another. The jaws are produced forwards, 

 and united into a tube, at the apex of which the mouth is situated. The swimming or air 

 bladder has no air duct leading to the throat. The gill apertures are small, one on either side 

 of the nape, and the gills, instead of being comb-like, assume a tuft-like or granulated struc- 

 ture, arranged upon two series and situated under large, convex, and bony opercles. There are 

 no cceca to the intestine. 



Syn. — Lophobranches, Cdv. Regn. Anim. I[, 1817, 155; 2d ed. II, 1829; &, ed. illustr. Poiss. 329. — Ddm. Ichth. analyt. 

 1856, 169. 

 Lophobranchii, Bonap. Sagg. Distr. metod. anim. vertebr, 1831, 119. — Richards. Faun. Bor. Amer. Ill, 183G, 

 276.— DeKat, New York Faun. IV, 1842, 319.— Mull, in Wiegm. Archiv fur Naturg. 1845, I, 137.— 

 Storer, Synops. 1846,238. — Owen, Lect. Comp. Anat Vert. Anim. 1846, 50. 



The members of this order are quite diversified in their external asjiect. From the Sea-Horse 

 {Hippocampus) to the flying sea-horse (Pegasus) there is a gradual transition, the orientation 

 excepted ; but from the latter to the Pipe-fish (Syngnathus) there is quite a step. The peculiar 

 structure of the gills appears to be the chief binding, trait between these extreme forms. 



In Hippocampus and Syngnathus the muscles presiding over the movements of the dorsal and 

 pectoral fins must assume a most perfect structure, if we are to judge of them by the action of 

 these fins. Every ray has a range of movements almost unequalled in the class of fish. These 

 are so rapid that the eye can hardly catch them while in motion — we were going to say in 

 vibration. They execute a series of undulations in the longitudinal and vertical directions so 

 as to simulate a screw in every sense of the word, and we would advise the inventive genius of 

 our mechanics who study the screw propelling problem to pause an instant before this organic 

 machinery, and ascertain whether nature has understood that problem as well as themselves. 



In either of the genera we have just been alluding to we find that the male sex is provided 

 with an elongated sub-caudal pouch, into which the eggs are sheltered, not merely until hatched, 

 but where the embryos themselves remain for a certain length of time. Some very peculiar 

 habits must be connected with this curious structure ; peculiarities connected with the fecunda- 

 tion of the eggs themselves and the moral tendencies of either sexes, since the male is made 

 here the exclusive guardian and protector of the progeny. 



In treating of the stickle-backs (Gasterosieiis) we have noticed traits somewhat parallel to 

 these : we allude to the construction of a nest by the male, and the watch he institutes over 

 the eggs therein laid by the female. — (See page 8G.) 



Similar facts in the class of fishes are no longer isolated, as they have been in the past 

 history of ichtliyology. The sun-fish {Pomotis), the cat-fish (Pimelodus) , and the lump-fish 



