158 



ri.ECTOGNATIIS.- 



-FISHES." 



-Ealistids. 



lionsile tails. The rings are mimerous, and various 

 knobs on tlio cranial bones, witli the elongated face, 

 |iroduce a resemblance to the head of a horse, which 

 was recognized in ancient times, as it is now by the 



present inhabitants of tho Mediterranean, by the appel- 

 lation of Sea-horses. Pliny, referring to these fishes, 

 says — "As, according to the common opinion, every- 

 thing that is produced on land has its marine repro- 



Pig. 41. 



Fatkhmd l^hiiid NeropUis (Nei'ophis hyiiienulomus). 



suntativc, our wonder ought to be the less on beholding 

 tho heads of horses springing from such tiny shells." 



The genera .are — nippocanipiis ; Acentrotiura ; Gasteroto- 

 kcus; Solc7inf]natlnis ; Phijllopteryx ; llallcampus; Trnchy- 

 rhamphtis ; Corijthoichthys ; Ichl/if/ocanipus ; Stinfjnathits ; 

 Iji'ptonotus ; Slphonostomus ; Leptoichthys ; StifjmaUiphura ; 

 1 >or}jrhamphn3 ; Doryichlhys ; Chveroicluhys ; Ileiniihylacus ," 

 Microphis ; and Nerophis. 



These, distributed into four subfamilies or tribes, are 

 described by Dr. Kaup in his Catalogue of Fish in the 

 ISritish Museum. The following are lirilish si)ccios — 

 The Short-nosed Hippocampus {Hippocampus hrevl- 

 rusiris); the Nccdlc-fish {Syiiffiiathus acus); the Deep- 



nosed Pipe-fish {Sij^Jiono-iloymis typ/hle) ; the .fliquorc.d 

 Pipe-fish {Nerophis cccpioreus) ; the Snake Pipe-fish 

 {Nerophis anrjuincus) ; the Straight- nosed Pipe-fish 

 {Nerophis ophidioii) ; the Worm Pipe-fish {Nerophis 

 lumbriciformis). 



In the Edinburgh New Philosophical Journal for 

 April, 1855, there is a statement of the ship Ilarhinga- 

 having sailed for several hundreds of miles in the 

 North Atlantic among shoals of dead fishes, supposed 

 to have beer] killed by subniarhie volcanic action. Cne 

 of these dead lish being sent to Sir William Jardine, 

 was determined by him to bo the common Snake Pijie- 

 lish {Nerophis (inrjuineus). 



Order Vlll. — PLECTOGN ATHS. 



In this order the maxillary bone is soldered to or 

 coalcscent with tho premaxillary of the same side, and 

 in some groups the conjoined bones of the one side are 

 blended on the mesial line with those of the other, 

 forming a solid upper jaw in which the teeth are incor- 

 porated, and which is opposed to a mandible of similar 

 form and dentition, having its limbs also coalescent at 

 the symphysis. In other groups the mesial junction of 

 the lateral halves of the jaws is in form of a serrated 

 suture. The internal skeleton is partially ossified, and 

 has a fibrous osteoid structure, without any bone cor- 

 puscles. The pieces of the skeleton are fewer than in 

 the Osseous fishes, having only rudimentary ribs, as 

 well as wanting some other bones; and the dermal 

 skeleton dilTeiing much in aspect from the ordinary 

 scales, is considered to approach ganoid scales in tex- 

 ture. The spines of the fins also, when present, are 

 studded with ganoid grains. Agassiz, because of the 

 structure of the dermal bony scales, is inclined to range 

 the order provisionally among his Ganoids ; but Muller, 

 who relies more on the forms of the central organ of 

 circulation, does not separate the group from the Osseous 

 fishes, with which its members agree in having merely 

 two valves at the origin of the arterial stem, without 

 the succeeding rows that exist in the Ganoids. The 

 swim-bladder of these fishes is closed, having no air- 

 duct, and there are no pancreatic caeca. The gills are 

 biserial, and the processes of one series alternate with 

 those of the other instead of being in opposite pairs. 

 There are no distinctly-developed ventrals, but their 



place is supplied in some groups by a projection of the 

 pubic bones, sometimes followed by a longitudinal series 

 of short slender spines. 



Family I.— BALISTIDS {Balistida). 

 Plate 13, fig. G5. 



The characters of this group are a conical face with 

 a small mouth at its apex, armed with a few more or 

 less tapering incisorial teeth. The skin is protected 

 by shield-like, ganoid scales, or by small rough points. 

 The branchife are three only. These are most gone- 

 rally considerably compressed fishes, with a profile often 

 approaching to oval or orbicular, but sometimes much 

 elongated. In one group, the Dalistini of authors, the 

 ganoid mail is divided by diagonal intersecting lines 

 into small rhomboidal discs ; t)io stout anterior ray of 

 the first dorsal is followed by one or two small ones, 

 which act as triggers to fix it in an erect position, and 

 when disengaged, allow it to fall back into a groove. 

 In the other group (tho Monacanthini) the dermal mail 

 is in form of small, thickly-set spines, of forms varying 

 with the species, and occasionally resembling in fine- 

 ness and closeness the pile of velvet, 



Tlie genera are — Pyrodvn ; Melichthys ; Xanthichtliys ; 

 Canthidermis ; Batistes ; Balistapus ; 3fonacarithus ; Alattrius ; 

 and Priacantkus. — (See Kaup, Cat. Brit. Mils.) 



The Pig-faced Trigger-fish or File-fish (Balistcs 

 ca2)risciis) is a British species, though very seldom cap- 



