cottidje. 477 



live in the northern half of the temperate zone. On the 

 shore, as well as in rivers, they prefer rooky or stony to 

 muddy ground, lying concealed between the stones, and 

 watching for their prey, which consists of small crustaceans 

 and other aquatic animals. The common British Miller's 

 Thumb (C. gobio) is found in almost all suitable fresh waters 

 of Northern and Central Europe, especially in small streams, 

 and extends into Northern Asia. Other freshwater species 

 abound in North America and Northern Asia. Cottiis 

 scorpius and C huialis, the common European marine species, 

 range across the Atlantic to the American coasts. The male 

 is said to construct a nest, for the reception of the spawn, of 

 sea-weeds and stones, and to anxiously watch and defend 

 his offspring. The spine at the angle of the prseoperculum, 

 which is simple in the majority of the freshwater species, is 

 frequently armed with accessory processes, and antler-like, 

 in marine. 



Cantrideemichthys differs from Cottus in having teeth on the 

 palatine bones. 



Eleven species are known, distributed like Cottus, but 

 absent in Europe and North-western Asia. 



IcELUS. — Head large, armed at the gill-covers and on the 

 neck ; body with a dorsal series of bony plates from the neck to 

 the base of the caudal ; lateral line with osseous tubercles ; 

 scattered scales on the sides and abdomen. Ventrals thoracic, 

 with less than five rays. No pectoral filaments. Villiform teeth 

 in the jaws, on the vomer and palatine bones. 



Eepresents Cottus in the far north; /. hamatus is common 

 in Spitzbergen and Greenland, and has been found in abun- 

 dance in lat. 81° 44'. 



Platycephalus. — Head broad, much depressed, more or less 

 armed with spines; body depressed behind the head, sub- 

 cylindrical towards the tail, covered with ctenoid scales. Two 

 dorsal fins ; the first spine isolated from the others. Ventrals 



