COTTID^ THE SCULPINS 325 



of special "grunting muscles" — an apparatus demonstrated by Prof. 

 R. W. Tower for the squeteague, a related marine species of drum.* 



Judging from the condition of specimens obtained, our sheeps- 

 head probably spawns in the latter part of May or the first of June. 

 This is not an angler's fish, but it is sometimes caught with crawfish 

 bait. 



The fact that the sheepshead and the white and the yellow bass 

 inhabit the same waters and frequent similar situations, the two bass 

 living on a similar food and the sheepshead on a widely different one, 

 gives to the local distribution of this group of three associate species 

 especial interest as illustrating the competitive relationship among 

 fishes. Comparing our 55 collections of the white bass and our 96 

 collections of the yellow bass with our 64 collections of the sheeps- 

 head, we find that the first two species have been taken together in 

 20 collections, that the white bass and the sheepshead have also 

 occurred in the same collections 20 times, and that the yellow bass 

 and the sheepshead have been taken together 31 times. The cor- 

 responding ratios of associative occurrence are 5.21 for the two 

 species of bass, 7 . 95 for the white bass and the sheepshead, and 

 11 .91 for the sheepshead and the yellow bass. That is, the species 

 which compete directly for the same food are found far less fre- 

 quently together in the same situations, proportionately to the 

 abundance of each, than are those which depend on different foods. 



Family COTTIDJE 

 (the sculpins) 



Body moderately elongate, fusiform or compressed, tapering back- 

 ward from the head, which is broad and depressed; body naked or vari- 

 ously armed with scales, prickles, or bony plates, never uniformly scaled; 

 lateral line present; skeleton osseous; vertebrae 30 to 50; ventrals tho- 

 racic, rarely wanting, I, 3 to I, S; dorsals separate or somewhat con- 

 nected, the spines 6 to 18, usually slender and sometimes concealed in 

 skin; anal fin without spines; caudal rounded; no mesocoracoid ; gills 3^ 

 or 4, the slit behind the last small or obsolete; gill-membranes broadly 

 connected, often joined to the isthmus; pseudobranchiae present; gill- 

 rakers short, tubercle-like or obsolete; preopercle usually with 1 or more 

 spinous processes at its upper angle; third suborbital connected with pre- 

 opercle by a bony backward extension or stay; premaxillary protractile; 

 no supplemental maxillary; teeth in villiform or cardiform bands on jaws, 

 and often on vomer and palatines; pyloric caeca usually 4 to 8 ; air-bladder 

 commonly wanting. 



*Sctence, Vol. XXII., p. 376. 



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