250 



LOWER VERTEBRATES. 



The Scorpwnichthys marmoratus, known along the Californian coast as cabezon, 

 sculpin, scorpion, salpa, and big-head (the last having the same meaning as cabezon) 

 IS the largest of the family, and the only one brought habitually to the markets. It 

 attains a length of ten to fifteen pounds, and is distinguishable by the development 

 of eleven dorsal spines and five ventral rays. 



The sculpins of the north Atlantic constitute the genus Cottus and have the gill 

 membrane free around the margin, and the spines of the head are very stout Three 

 species occur along the coast of the Eastern States,- C. octodecimspinosns, C 

 CB7ieus, and C. grcenla7idiciis. 



_ The miller's-thumbs of the fresh waters belong to another genus named Uranidea ■ 

 in these the gill-membrane is confluent with the skin of the throat, the gill holes being 

 limited to the sides, and the spines of the head are very feeble and partly wanting 



Fig. 141. — Cottus scorpiOy sculpin. 



The species are quite generally distributed over the northern hemisphere, and are 

 very closely related. The commonest of European species is H. ffobio, and of Ameri- 

 can, IT. gracilis and TT. viscosa. 



There are certain fishes, the largest and best known of which is commonly called 

 the lump-fish, which constitute a peculiar family — Ctclopteeid^ — apparently 

 related to the Cottidfe, although they have been generally widely separated from 

 them. The body is short and tumid, and tubercles generally surmount the skin, but 

 sometimes they are wanting, leaving the surface smooth ; the head is short and wide 

 and covered by the skin, all armature being suppressed; there are two dorsals; 

 the first is short and spiniferous, but sometimes overgrown by the skin ; the pectorals 

 have wide procurrent bases, and, above all, the ventral fins are united in a circular 

 disk. The bones are imperfectly ossified, and the entire appearance indicates that 

 the species are the degenerate descendants of nobler fishes. They are most nearly 



