BO 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
frequently met with, and in lobsters from 3 to 4 inches long, under very peculiar cir- 
cumstances. (See pp. 89 and 90.) Coarse sand and gravel-stones, occasionally as large 
as duck shot, may also be found in the stomach, but with no marked regularity. 
These are not necessary for grinding the food, as in the gizzards of fowls, since the 
walls of the lobster’s stomach are furnished with an admirable masticatory apparatus; 
still, whether of accidental occurrence or not, they can hardly fail to serve a useful 
purpose. 
In the course of this investigation of the habits of the lobster, the stomachs of 
large numbers of these animals were carefully preserved during a period of seven 
months (December to June). They were all captured in the harbor of Woods Hole, 
Massachusetts, under the conditions described on p. 25. A considerable number 
of these stomachs were empty ; more than half contained remnants of recently devoured 
tish, a mass of scales and bones, mixed with fragments of the indigestible parts of 
other organisms. In many cases it was quite evident that the bait of the traps 
formed the only food found in their stomachs. 
The lobster undoubtedly regurgitates the insoluble and indigestible parts of 
its food. That the crayfish possesses this power was shown by the experiments of 
Lemoiue (118). When the buccal cavity was stimulated by electricity, antiperistaltic 
movements were set up in the remaining parts, until the contents of the stomach 
escaped by the mouth. It was thus proved that the oesophagus was capable of two 
kinds of movements — peristaltic and antiperistaltic. Some such outlet for waste 
matter is absolutely necessary in an animal where the fluid or finely divided and 
digestible parts of the food only can pass into the delicate intestine. The hard parts 
of fish, mollusks, and Crustacea appear to be retained until they have given up a good 
deal of their lime, thus contributing to the calcareous supply of the exoskeleton. 
The stomachs examined contained remnants of the following organisms placed in 
the order of their relative abundance: fish (procured independently of the traps); 
Crustacea, embracing chiefly isopods and decapods; mollusca, consisting largely of 
small univalves; algae; echinoderms and hydroids. The bones of fish showed them 
to belong, as a rule, to small individuals or species. Among the crustacean remains 
parts of the small mud-crab, Panopaeus (P. sayi and P. depressus, the common species 
in Vineyard Sound) were almost invariably recognized, and it was not unusual to find 
parts of the skeletons of small lobsters. The isopod, Givolana concharum , is frequently 
eaten by the lobster, often in large numbers. This species is a scavenger, and 
devours the bait used in the traps, which explains its common occurrence in the 
stomachs of lobsters recently caught. In one case, that of a female captured in January, 
the stomach was filled with fresh lobster eggs in an advanced stage of development. 
These were not taken from any lobsters in the trap, but under what circumstances 
they were obtained one can easily conjecture. The egg-lobster is undoubtedly a shining 
mark, not only for outside enemies, but even for members of its own species. The 
larger mollusks are eaten by crushing the shells and picking out the soft parts, while 
many of the smaller species are swallowed entire, and afterwards pulverized in the 
gastric mill. Echinoderms probably enter largely into the diet of the lobster, wher- 
ever they abound. Parts of the common starfish (Asterias forbesii) and rarely a few 
spines of the sea-urchin (Arbacia punctulata) were detected, but it might be that the 
latter were swallowed together with other calcareous fragments. Very little change 
