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BULLETIN OF THE UNITED STATES FISH COMMISSION. 
described from Cambarus propinquus by Wright and Linton, and Ward (198) has found 
in the same crustacean still another species, Distoma opacum. “The cysts occupied 
the space in the cephalothorax above the heart and sexual organs.” 
The “ tomally” or liver of the lobster is free, so far as is known, from parasites 
of all kinds, yet this is not the case with all the decapod Crustacea. In June, 1885, 
while dissecting the southern shrimp ( Penceus setiferus ), I found numerous stages in the 
development of a cestode worm, Tetrarhynclms (species undetermined), in the liver of 
this prawn. The youngest were oval, about inch in long diameter; the oldest 
larvae measured T V inch ; they had a round, flattened body, an anterior segment or 
neck, with four well-developed proboscides, and a “tail” of about equal length, and 
unsegmented. Two pairs of bright red pigment spots were borne on the upper ante- 
rior part of the body. 
DISEASES OF THE LOBSTER. 
There are no specific diseases to which lobsters are subject, so far as known, yet 
they sometimes die off so rapidly as to lead one to suspect that they may have fallen 
a prey to some contagious disease. 
Mr. 1ST. F. Trefethen, of Portland, Maine, who owns a lobster pound in South 
Bristol, 35 miles east of Portland, relates the following experience: In May, 1893, 
he placed 100,000 lobsters in this pound, the area of which is about 3 acres. Very 
soon they began to die, and in a few days all of them were dead. There were 12 
to 13 feet of water in this pound at flood tide and not less than 9 feet at low water. 
The pound was probably very much overstocked, but it is difficult to understand why 
these lobsters should have all died so suddenly, unless they were either poisoned or 
attacked by disease. 
In the summer of 1889 a lobster with a large bunch on the side of the carapace 
was captured in Vineyard Sound. On the top of this tumoid growth was a crater- 
like depression covered with a membrane. This was probably a sore resulting from a 
wound which the animal had received in the back, and which had failed to heal. A 
similar case is mentioned by Rathbun (155). 
