Helminth Fauna of the Dry Tortugas. 61 



sucker; prostate large, extending from dorsal side of ventral sucker pos- 

 teriorly for a greater distance than the diameter of the venti'al sucker. 

 The seminal vesicle is relatively large, oval, and is inclosed in a muscular 

 wall; it lies dorsal to the posterior end of the prostate and immediately 

 in front of the testes. The testes are 2, small, globular, close together, 

 ventral and slightly diagonally placed. The ovary lies some distance be- 

 hind the testes, its longer diameter transverse to the axis of the body. 

 At its posterior border lie the 2 yolk-glands, the right being globular or 

 oblong elliptical, the left more or less 3-lobed. The folds of the uterus 

 are for the most part between the seminal vesicle and the base of the ap- 

 pendix. The excretory vessels are not distinct in the mounted specimens. 



This distome agrees closely with Hemiurus appendiculatus as de- 

 scribed by Looss (Zool. Jahrb., 1907, p. 103, plate 7, figs, i, 2, 3). The 

 most marked difference is in the character of the seminal vesicle, which 

 is not divided into two portions, but consists of a single, oval structure, 

 inclosed in a strong, muscular wall and with its longer axis coinciding 

 with the long axis of the body. 



Host, Clupanodon pseudohispaniciis : July 10, 1906, few. 



Dimensions, life: Length 2.94; breadth 0.5; oral sucker 0.09; phar- 

 ynx 0.07; ventral sucker 0.21 ; ova 0.027 by o.oio. 



Sterrhurus monticellii (Linton). (Figs. 139, 140.) 



Distomv.m monlicellii, Proc. U. S. Nat. Mus., pp. 51S-520, plate xliv, figs. 2-8. 

 Bull. U. S. Fish Commission, 1899, pp. 451, 473, 482. Bull. Bureau of 

 Fisheries, vol. xxiv, p. 334, figs. 154, 155, 158. 



The distomes upon which this description is based were collected 

 from a remora which had been taken on a tiger shark before I reached 

 the laboratory, and had been preserved in formalin. The stained and 

 mounted material shows but a part of the anatomy, but so far as can be 

 seen they agree with the species which I have recorded under the name 

 Distomum monticellii. This distome agrees closely with the genus Ster- 

 rhurus Looss. 



Following are the characters that can be made out from these dis- 

 tomes: Body smooth, nearly cylindrical, largest near posterior at level 

 of o varv ; ventral sucker 2 . 5 times the diameter of oral sucker ; seminal 

 vesicle elongated, situated at cephalo-dorsal border of ventral sucker and 

 preceded by the prostate. Intestinal rami long. Testes small, close 

 together, one behind the other and close to the posterior edge of the 

 ventral sucker; ovary larger, separated from the testes by folds of the 

 uterus; yolk-glands 2, at posterior border of the ovary, each rather deeply 

 lobed; uterus filling a large part of the body. 



Dimensions, balsam: Length 1.45; breadth 0.35; oral sucker 0.12; 

 pharynx 0.06; ventral sucker 0.35; ova 0.02 by o.oi. 



Transverse and tangential sections were cut of these distomes; of 

 these the tangential were the most satisfactory. From them it was 

 seen that there is a seminal receptacle situated caudo-dorsad of the yolk- 

 glands. There is a deep cleft (fig. 139 n) on the ventral side of the neck, 

 immediately in front of the ventral sucker, which has a thick, muscular 

 wall at its inner end. The genital pore is close behind the oral sucker. 



