512 Roosevelt inid Life .Innals 



Cottus bairdii Girard. ^Millers Thumb, Common Sculpin, Mudler. 

 Little was learned of the numbers of the Miller's Thumb in Oneida Lake, for it is 

 not easily captured in a net. For this reason and on account of the small size of 

 the species and its habit of lying close to the bottom, which it closely resembles, 

 it is not well known to persons who are not students of fish. It is rather grotesque 

 in appearance, having a very large head in proportion to its body which tapers to a 

 small tail. The mouth is very large, and there are curved lateral spines on the 

 head. The skin is naked, except for some prickles behind the large pectoral fins 

 in some examples of the species. This fcirni is not easly distinguished from its 

 near relative, Cottus cogiiatits Richardson, which is abundant in neighboring waters, 

 for example, Onondaga Creek at Syracuse, and which possibly may also be found 

 in Oneida Lake. Specimens on hand are distinguished by the four soft anal rays 

 in addition to the concealed spine, while C. cognatus usually has three soft rays. 



Breeding Habits and Life History. Cage (Gill, '08, p. 1 1 1) found in Cayuga 

 Lake, New York, eggs of a fish that in all probability was this species. The eggs 

 were in irregular conical masses and of salmon color. Each mass was hanging on 

 the lower side of a flat stone in water five or six inches deep, and was guarded by 

 a male. They were found from April to July. Hay ('94, p. 291) quotes J. P. 

 Moore as saying that the eggs of the ]\Iiller's Thumb (Cottus sp. ) in Indiana are 

 laid in masses of one hundred twenty to five hundred and that they cohere firmly, 

 but with open spaces between them allowing the circulation of water and the escape 

 of young from the interior of the mass, which may hatch first. The eggs hatch in 

 May. Hankinson (08, p. 216) found a cluster of eggs of the Miller's Thumb 

 (probably Cottus bairdii) on the under side of a stone on a gravelly shoal in 

 Walnut Lake. Reighard ('15, p. 239) found them in similar situations, and in 

 Douglas Lake he found Cottus only in localities that furnished nesting sites. 

 Recently Dr. Bertram G. Smith ('22) has published observations on the nesting of 

 Cottus bairdii near Ypsilanti, Michigan. He found egg masses consisting of about 

 200 eggs each, on the lower surfaces of stones in a small creek, and usually in 

 rather swift water. There was an adult attending the eggs in most cases. Hahn 

 {'2y. p. 430) who made observations on the breeding of this species near Ann 

 Arbor. Michigan, says: "At spawning time, the male prepares the nest under a 

 stone or some other favorable object. The nest consists only of a hole, which is 

 provided with a suitable covering and which can be easily protected against 

 enemies. The nest is then visited by one or more females, and eggs are deposited 

 on the under surface of the stone or other object which covers the nest. The 

 female then leaves, and the male guards the nest throughout the incubation period. 

 According to Mr. Carl L. Hubbs, Cottus bairdii, in the colder streams of northern 

 Michigan, is more common in the den.se patches of vegetation than under stones, 

 and to some degree at least deposits eggs on the plants. In warmer streams he 

 finds it more common under stones, particularly at breeding time. During the 

 breeding season, one may frequently find Cottus nests by carefully lifting the 

 stones in a place where the current is rather swift." Greeley i'2~, p. 65) mentions 

 the finding of a sculpin with eggs, by Messrs. Smith and Hering, on June 26, at 

 Nigger Spring, .\llcgany Co., N. Y. The eggs were spherical and in a grape-like 

 mass of abiiut 200. Ivich egg measured ;ibiiut 's iiH'h in diameter. The lish may 

 grow t(i a length of seven iiu-hes, .-iccnrding l.i bivdan and blverniann ( 'wS. ]). IU51,). 



