Glass 2, Pisces. Order 5. Teleostei. 391 



13. The Pediculati, with bulky, naked body; head often large; gill- 

 opening small ; pelvic . fins in front of the pectorals, the latter stalked ; the 

 radialia, which are short in other Teleostei, are long here ; the anterior portion 

 of the dorsal fin consists of a number of free rays. The only form occurring in 

 Northern Seas is the large Trog-fish (Lophius piscatorius), iiattened; with 

 a huge mouth; the free dorsal rays elongate, the most anterior with a soft 

 appendage at its tip. 



14. The Plectognathi are fish of very varied appearance, which agree 

 in having the premaxilhe and maxiUse, contraiy to the general rule, fiMnly 

 attached to the skull ; pelvic fins absent. Chiefly animals of very aberrant foitn 

 inhabiting the warmer seas. The Trunk-fish {Ostracion), short, with 

 flattened abdomen, peculiar in that most of the body is covered by a thin armom- 

 formed of polygonal bony plates, fijrmly connected together ; the small tail and 

 the fins alone are movable. The Sea Hedgehog (Diodon) is beset with 

 bony spines, which stand up when the animal puffs itself out ; this is effected by 

 filling a sac-like evagination of the oesophagus with air, which is taken in through 

 the mouth ; the creature then hes in the water with the ventral surface upwards ; 

 the dentition recalls that of the Parrot-fish. The Sun -fish (Mola or 

 Orthag orisons) is a large pelagic form, much compressed and very short, the 

 body forming a perpendicular oval disc ; the caudal fin is a ridge along the 

 hinder, edge of the animal, dorsal and anal fins high. 



15. The Sea-adder family (Syngnathidx). Body elongate, covered 

 with bony plates ; snout drawn out into a tube, at the apex of which lies the small 

 edentulous mouth ; pelvic fins absent ; gill-lameUee on each bar iu quite small 

 numbers, but much folded ; external branchial aperture small. The eggs ai-e 

 carried by the males on the lower side of the body and taU, sometimes simply 

 adhering to this ; in other cases enclosed in two longitudinal folds or in a sac. 

 The animals swim by a very rapid undulating movement of the rather shoi-t 

 dorsal fin (or of the pectorals, if these are present). Various forms inhabit 

 northern seas ; species of the genus Syngnathus, NeropMs, etc., in the last of 

 which only the dorsal fin is present. The Sea-horses (Hippocampus), with 

 finless, prehensile tail ; ventraUy curved head ; and spiny outgrowths on head and 

 body, swini in a perpendicular position ; usually in warm seas ; one species, 

 a,bundant in the Mediterranean," also occui-s in the North Sea. 



Class 3. Amphibia. 



The head, unlike that of Pisces, is, in Amphibia, generally 

 clearly defined, and is usually capable, to some extent, of free move- 

 ment, although there is no distinct neck. The head, and usualty 

 the body also, is somewhat flattened. The tail, when present, is 

 compressed and strongly developed, though not nearly so muscular 

 as in Fish ; dorsally, it passes gradually into the trunk, but 

 ventrally, is more sharply limited. The limbs have reached a higher 

 .stage of development than in Pisces : they are separated by joints 

 into several regions, of which the distal is divided into digits. 

 They have been modified to form ambulatory organs, which, 

 compared with those of the Mammalia, at least in one of the principal 

 groups (the Urodela), are small and feeble. 



The epidermis in the adult exhibits a thin stratum 

 corneum, only one or two cells thick, which, as in many Reptiles, 



