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TRANSACTIONS OF THE AMERICAN PHILOSOPHICAL SOCIETY 



Cottids. — Another great subdivision of the scorpaenoid series produced a highly diversi- 

 fied family, the Cottidae, especially characteristic of northern waters. These are mostly 

 long-bodied with very large pectoral fins, long and divided dorsal fin, large tails, big eyes 

 and protruding lips. The spikes on the preopercular border vary greatly; they are often 

 reduced to two conspicuous ones and of these the upper is much produced, sometimes form- 

 ing a curved hook either with lateral accessory processes (Icelinus) or without them {Arte- 

 diellus). A curved preopercular spike with two small upwardly directed accessory spikes 

 similar to that of Icelinus borealis (Jordan and Evermann, 1896, PI. CCLXXXIV) is found 

 in Callionymus rubrovinctus Gilbert (Gilbert, 1905, p. 650) belonging to an entirely difi"erent 

 family and suborder. 



The Coitus octodecimspinosus (Fig. 212) of Allis's monograph appears to be identical 

 with Myoxocephalus octodecimspinosus, several of which have been available for study. 



f^ sphot hyom pa pto ^^^ 



melh na 



Fig. 210. Ophiodon. 



This marine form seems to be near the base of the family. Its skull is characterized by the 

 presence of two very large spikes, one on the opercular, the other on the preopercular, which 

 point backward over the opercular cleft. A very small spike lies immediately below the big 

 one on the preopercular border. These two preopercular spikes have every appearance of 

 being homologous with the two preopercular spikes of Scorpana scrofa and with the main 

 two of the five preopercular spikes of Sebastes marinus. That at least the large spike has 

 some value as a weapon is suggested by the presence of a similar spike on the opercular and 

 of smaller ones on the cleithrum and supracleithrum, all pointing outward and backward 

 and collectively forming a sort of chevaux-de-frise. The preopercular has lost its squamous 

 expansion and now consists chiefly of a narrow bent rod, very densely built to support its 

 huge spike and tunneled from top to bottom by the lateral line canal. Six openings to the 

 latter on the posterior border mark the position of short side branches. The lower end of 



