COTTUXZE-^THE SOULPINS 325 



demonstrated by Prof. R. W. Tower for the squeteague, a 

 related marine species of drum.* 



Judging from the condition of specimens obtained, our 

 sheepshead 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 com- 

 petitive relationship among fishes. Comparing our 55 collec- 

 tions of the white bass and our 96 collections of the yellow bass 

 with our 64 collections of the sheepshead, 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 sheeps- 

 head have been taken together 31 times. The corresponding 

 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 frequently 

 together in the same situations, proportionately to the abun- 

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



FAMILY COTTID^E 



THE SCULPINS 



Body moderately elongate, fusiform or compressed, tapering backward 

 from the head, which is broad and depressed; body naked or variously armed 

 with scales, prickles, or bony plates, never uniformly scaled; lateral line 

 present; skeleton osseous; vertebra? 30 to 50; ventrals thoracic, rarely wanting, 

 I, 3 to I, 5; dorsals separate or somewhat connected, the spines 6 to 18, usually 

 slender and sometimes concealed in skin; anal fin without spines; caudal 

 rounded; no mesocoracoid ; gills 3 l / or 4, the slit behind the last small or 

 obsolete; gill-membranes broadly connected, often joined to the isthmus; 

 pseudobranchise present; gill-rakers short, tubercle-like or obsolete; pre- 

 opercle usually with 1 or more spinous processes at its upper angle; third sub- 

 orbital connected with preopercle by a bony backward extension or stay; pre- 

 maxillary protractile; no supplemental maxillary; teeth in villiform or cardi- 

 form bands on jaws, and often on vomer and palatines; pyloric caeca usually 

 4 to 8; air-bladder commonly wanting. 



* Science, Vol. XXII., p. 376. 



