FISHES 277 



is situated. Scales are absent, but their place is taken by bony 

 plates developed in the deeper part of the skin and arranged in 

 regular transverse rings. The name of the group (Gk. lophos, 

 a tuft; branchia, gills) has reference to the gill-filaments, which 

 are arranged in tufts and not in combs as in ordinary Teleosts. 

 The male fish usually has a pouch in the skin on the under side 

 of the body in which the eggs are developed and the young 

 protected. 



The Great Pipe- Fish (Syngnathus acus] is 

 a common British species, with much-elongated 

 cylindrical body and a small caudal fin. A 

 much more extraordinary looking species is the 

 Short-snouted Sea- Horse (Hippocampus anti- 

 quorum) (fig. 1 64), which has a very wide range 

 and is sometimes found off the British coast. 

 The name is suggested by the shape of the 

 head, which is sharply bent on the trunk and 

 separated from it by a sort of neck. The 

 animal maintains a vertical position in the Fi g . i6 4 .-sea-Horse (#/#* 

 water, both when swimming and also when 

 attached to sea-weed by means of its prehensile tail, which is 

 devoid of a caudal fin. 



Sub-order 3. FIRM-JAWED FISHES (Plectognathi) 



This also is a small group, embodying about 180 species, 

 most of which have a well-developed external skeleton. There 

 is as a rule nothing to correspond to the spiny first dorsal and 

 pelvic fins of a perch, except, perhaps, a few spines. The gill- 

 cover is not a large free flap, but is united with the surrounding 

 parts so as to leave only a small aperture through which the 

 water which has passed over the gills can flow out to the exterior. 

 The internal skeleton is deficient in bony matter, but the bones 

 of the upper jaw are very firm and fused to the main mass of 

 the skull, a feature which the name of the sub-order suggests 

 {Gk. plektos, woven together; gnathos, jaw). The included species 

 are characteristic of tropical seas, though not confined to them, 

 and include: i. File-Fishes; 2. Coffer- Fishes; 3. Globe-Fishes; 

 and 4. Sun-Fishes. 



i. File- Fishes constitute a widely distributed family, in which 



