438 DISTRIBUTION IN SPACE AND TIME 



(Callionymus), and, in warmer countries, the little Mud- Skippers 

 (Periophtkalmus and Boleophthalmus), the habits of which have 

 already been noticed. Other families are those which include 

 the Blennies (Blenniidtz), many of the Bull- Heads (Cottid&)^ and 

 the gorgeously tinted Wrasses (Labndtz). There are also the 

 curious Pipe -Fishes (Syngnat hides), remarkable for the brood- 

 pouch possessed by the male, and among these are the Sea- 

 Pi orses (Hippocampus, Phyllopteryx, &cf), which are not found 

 in British seas. 



Primitive Vertebrates (Protochordatd) of the Neritic Zone. 

 Lancelets (Amphioxus) and Acorn-headed Worms (Balanoglossus) 



Fig. 1292. Coral- Fish (Epiuephelus hexagonatus] 



are widely distributed neritic forms, with burrowing habits. The 

 zone is also inhabited by large numbers of Ascidians or Sea- 

 Squirts (Urochorda), some solitary and some colonial, which in 

 their adult stage are attached to various objects. 



Neritic Molluscs (Mollusca). Head-footed Molluscs (Cepha- 

 lopoda) abound in shallow water, Squids and Cuttle -Fishes, for 

 instance, being found in large numbers around our own coasts, 

 while eight-armed forms, such as the Poulpe (Octopus) and its 

 allies, belong as much to the Benthos as to the Nekton, of the 

 Neritic region, for they crawl as much as they swim, or possibly 

 more so. 



Sea-Snails and Sea-Slugs (Gastropoda) simply swarm both 

 in shallow water and between tide-marks, especially in the tropics. 

 Among the commonest littoral forms on the British coasts are 

 the Limpets (Patella], which adhere so closely to the rocks that 

 they defy the wash of the tide, to which their conical shell affords 

 but little purchase; the Purple-Shells (Purpura lapilhis), well 



