[79] NOTES ON ENTOZOA OF MARINE FISHES. 797 



emended description of the species, together with some additional data 

 resulting from a study of living specimens : 



Head, when bothria are at rest, pyramidal, bothria four, triangular 

 or ovate, terminating in front in a narrow rounded point, broadly 

 rounded at posterior end, with a thickened, entire border, sessile, or at 

 least pedicels not evident. Each bothrium terminated at anterior end 

 by a supplemental disk. Neck long. First segment squarish, subse- 

 quently longer than broad ; posterior segments four or five times as long 

 as broad and usually rounded at the extremities. Neck and segments 

 with fine parallel, trausverse furrows which give a serrate outline to 

 margins. Genital apertures marginal, opening near anterior fourth. 

 Length as great as 35 mm . 



Habitat. — Garcharias obscurus, spiral valve, very abundant ; July and 

 August, Wood's Holl, Massachusetts. 



The following measurements of strobile and last segment are from the 

 living specimens : 



Dimensions. 



Length 



Length of last segment. . 

 Breadth of last segment. 



No. 1. No. 2. No. 3. 



mm. 



35. 50 

 3.00 

 0.50 



mm. 



32.00 

 2.50 

 0.55 



mm. 

 17.50 

 1.60 

 0.30 



The following additional measurements are from No. 3, specimen 

 slightly flattened under the compressor: Breadth of head, anterior, 

 .32 mm : breadth of head, posterior, ,6 mm ; length of neck, 2.8 nun ; breadth, 

 .18 mm ; length of first distinct segment .2 mm , breadth, .36 mm . 



One lot of specimens obtained August 12 contained only sixteen in- 

 dividuals of this species. On July 25, however, a very careful search 

 was made for Entozoa in a dusky shark and with astonishing results. 

 Besides several specimens of Anthobothrium laciniatum and Phoreio- 

 bothrium lasium, there were in the neighborhood of four hundred speci- 

 mens of Tetrarhynchus bisulcatus and enormous numbers of the species 

 under consideration. The chyle of the intestine was absolutely swarm- 

 ing with them. They were saved and partially assorted at the Wood's 

 Holl laboratory. During the following winter I attempted to com- 

 plete the assorting of this lot in order to find out the exact number 

 of these parasites, but found the work insufferably tedious. The worms 

 are in many cases felted together in a tangled mass which can not be 

 untangled except by mutilating the strobiles. This peculiar felting 

 together along with a kind of tough or indurated secretion was observed 

 when the worms were first removed from their host. I have examined 

 this unassorted lot carefully for other species, but succeeded in finding 

 only the species mentioned above, which were separated from the lot 

 at the time of collecting. 



Desiring to form some idea of the number of individuals in this lot, 

 I attempted to separate them from the tangle of strobiles and chyle, so 



