UNUTILIZED FISHES. 25 



In San Francisco the French and Italians are said to buy skates, 

 which they relish as a food. The trade, however, is very small. 



At Chilmark, Marthas Vineyard, during these observations, the 

 only purpose for which skates were seen to be used by the fishermen 

 was as bait for lobster and eel pots. Skates have, however, been 

 used as fertilizer. Goode (1887) reports having seen them at fac- 

 tories put in the boilers with certain other fishes. An article in the 

 Yarmouth Register for June, 1870, states that Mr. Wilson Reyder, 

 of Barnstable, used many cartloads of skates for manure ; and that 

 Enoch F. Reyder found it remunerative to boil them down and con- 

 vert them into guano, after oil had been extracted from the livers. 

 Skates are not utilized extensively in this country, however. More- 

 over, little seems to be known about their general habits and economic 

 relations. 



FOOD. 



A general account in the Standard Natural History, vol. iii, 

 states the food of the skate to be shellfish, crabs, flounders, and 

 other bottom frequenting forms. To capture the prey " the ray 

 swims rapidly over a fish, and then settles down upon it, holding it 

 from escajDe with its broad body; then by suitable muscles, the jaws 

 are protruded beyond the rest of the surface and the object is 

 taken in."' 



The best food record of the species is contributed by Linton (1901), 

 and reads thus : 



Usually Crustacea and annelids, but bivalve mollusks, squid, and fish are also 

 frequently found in the stomach. In the summer of 1899 thirty-two skates were 

 examined and the following food material noted: Crabs (hermit. Cancer, 

 CalUnectes, Panopeus, and others), shrimps, amphipods, annelids, squid, bivalve 

 mollusks, small fish. 



EXAMINATION OF DIGESTIVE TRACTS. 



My own results, obtained from the examination of the alimentary 

 tracts of 516 summer skates, and briefly shown in the accompanying 

 table, are thoroughly in accord with the foregoing statements. More 

 than 29 per cent of the 516 skates contained crabs {Cancel', OvaUpes, 

 Panopeus, and Pagurus), most of which were the common rock crab 

 (Cancer irroratus). The shrimp {Crago septemspinosus) is also 

 devoured in great numbers, nearly 15 per cent of the skates contain- 

 ing it in larger or smaller quantities ; and a few specimens contained 

 amphipods in considerable numbers, making the total number of 

 skates which had eaten Crustacea very large. 

 506—07 4 



