IV.—NOTES ON ENTOZOA OF MARINE FISHES OF NEW ENG- 
LAND, WITH DESCRIPTIONS OF SEVERAL NEW SPECIES. 
By EpwIn LINTON. 
In the summers of 1884-85 I collected Entozoa from several of the 
commoner species of food-fishes and Selachians at the summer station 
of the U.S. Fish Commission, Wood’s Holl, Mass. 
Cestoid entozoa in the adult or strobile condition were found in great 
numbers in the alimentary tracts of all the Selachians examined. En- 
cysted forms of the Cestoidea are for the most part confined to the 
Teleostet and are found in greatest abundance in the submucous coat 
of the stomach and intestine, although not infrequently met with in 
the peritoneum, liver, spleen, ovaries, &c. In every specimen of such 
fishes, as the Bluefish (Pomatomus saltatrix), Squeteague (Cynoscion 
regale), Striped Bass (Roccus lineatus), &c., examined, the walls of the 
alimentary tract were spotted thickly with minute cysts, which, when 
opened, were found to contain larve of some Cestods, most of them of | 
the genus Lhynchobothrium. Some from the submucous coat of the 
Squeteague (C. regale) seem to be larve of the species which I have 
named R. bisulcatum. 
In the gall-bladder of nearly every specimen of Squeteague (Cynoscion 
regale) that I have examined, I found hundreds of larval Tetrabothria. 
They are usually attached to the walls of the cystic duct in clusters of 
such size as to obstruct the passage. (Plate VI, Figs.6and7.) They 
are easily dislodged and often may be seen in vast numbers in the amber- 
colored contents of the gall-bladder. These larve, when placed in sea- 
water, are quite active. Each moves by alternately thrusting forward a 
pair of bothria and by alternate contraction and extension of the body. 
While this is in progress the body is constantly changing its form. At 
times it is long and filiform, at others short and broad. At rest it is 
commonly thickened or obtuse in front, tapering posteriorly. The body 
of the larva consists of a thin limiting membrane about 0.05™™ thick, 
inside of which is a granular parenchyma, the latter a clear fluid filled 
with highly refractile globular masses averaging 0.01™™ in diameter. 
The bothria are four in- number, without hooks, and in the majority of 
those examined, without coste. In some specimens there seems to be 
the beginning of an auxiliary acetabulum at the apex of each bothrium. 
[1] 453 
