FISH PARASITES COLLECTED AT WOODS HOLE. 28!) 



Distomum appeudiculatuni Rudolph! (f). 

 [Plato 30, figs. 25, 26, U. S. N. M. No. 051 1. 1 



Two small distoma, associated with D. dentatum, from the flounder (FaraUchthys dentatna), belong- 

 to the subgeuus Apoblema and appear to be near I), appendiculatum. The specimens, while quite 

 Hin.-ill, are adult, each containing numerous ova. Collected August 27. 



The following description is based on a mounted specimen: Body cylindrical, crossed byline 

 transverse stria- about 0. 005 millimeter apart. These stria: are sharp and (dear and make a regular 

 serrate outline at the margins; neck short, conical, concave beneath; mouth siibturminal ; acetabulnm 

 at base of neck about twiee the diameter of the oral sucker, both suckers nearly globular; seminal 

 vesicle a short distance back of acetabuluui situated toward dorsal side; between it and the acetab- 

 uluui is the largo prostate and cirrus pouch. The external reproductive aperture is on the mid ventral 

 line very close to the mouth ; cirrus smooth. The testes are two small subglobular bodies about 0.17 

 mm. behind the acetabulum, veutrally placed and lying diagonally near together on the median line. 

 The vitellaria are two small but well-defined bodies lying ventrally a little toward the light, their 

 front margins about half way between the acetabulum and the end of the body proper; the right lobe 

 is subglobular, the left somewhat three-lobed. The folds of the uterus do not extend into the appendix ; 

 ova numerous, lying among the reproductive organs from behind the testos to the acetabulum; ovary 

 globular, lying just in front of the vitellaria slightly dorsal to and touching them. 



Dimensions of mounted specimen, in millimeters: Length with appendix 1.13, length without 

 appendix 0.92, greatest diameter 0.25, diameter of oral sucker 0.065, diameter of acetabulum 0.12, 

 length of pharynx 0.05, diameter of pharynx 0.04, longer diameter of ova 0.027, shorter diameter of 

 ova 0.014. 



It will be noticed that while the proportions of the suckers are those of D. appendiculatum the 

 character of the vitellaria shows a dissimilarity to that species. 



Distomum fcecundum sp. uov. 

 [Plate 36, tigs. 27-35; Plate 37, figs. 36, 37, U. S. N. M. No. 6512.] 



On September 1 the viscera of live tilo-tish (Lopliolatilus chamnleonticeps) taken in 75 fathoms 

 of water, south of Newport, K. I., were placed in formalin. On September 5 I examined these viscera 

 for eutozoa, finding but few, and only one specinian of Distomum. 



The specimen being too thick to permit of a satisfactory examination of the internal structure, 

 it was cut into transverse sections. A study of these yielded such interesting results that I feel 

 justified in recording the following description: Body unarmed, smooth save for transverse wrinkles 

 probably due to contraction, thick, bluntly rounded in front, squarish posteriorly; neck slightly 

 excavate beneath; mouth subterniinal, circular; acetabulum much larger than oral sucker, sessile, 

 prominent, its aperture a transverse slit; pharynx subglobular; oesophagus very short; branches of 

 intestine simple, extending to posterior end; genital aperture in front of acetabulum a little to right 

 of median line; cirrus and pouch for the greater part dorsal to acetabulum, seminal vesicle dorsal on 

 left side just in front of ovary, vas deferens accompanied by prostate from seminal vesicle to cirrus 

 also dorsal; ovary dorsal back of posterior third on median line; testes two, transverse, the right a 

 little in advance of the other, following the ovary posteriorly, but situated more ventrally than ovary. 



In sections proceeding from the head the right testis appears soon after the ovary is first seen, 

 and continues to show in sections after the ovary has disappeared. The shell-gland is ventral to the 

 ovary. Vitellaria not abundant in this specimen, which is adult, situated along the dorso-lateral 

 regions of the body from the testes to the posterior edge of the acetabulum. The excretory vessel was 

 traced from the terminal pore, as a single narrow median canal, to a point in front of the ovary, 

 where it divides, the two branches passing one on either side of the acetabulum ventral to the 

 intestine. The most conspicuous organ in this specimen is the uterus. Its folds lill the body from 

 the posterior end to the acetabulum. Both behind and in front of the ovary and testes the uterus 

 occupies the whole cavity, save the small place occupied by the intestinal branches and excretory 

 vessels. The ova, of which there are immense numbers, are small, oblong-elliptical in outline, with 

 thin shell. The contents of a great many of them were stained deeply with carmine. Many of them 

 were broken open in the same manner at one end as if a natural line of cleavage existed there, causing 

 a terminal cap- like part of the shell to separate. The cells which line the intestinal tract are long 

 and project into the lumen with their bluntly rounded and slightly enlarged ends. 



Dimensions in millimeters: (1) Specimen entire in oil of cedar. Length 2.75, breadth through 



F. C. li. 188U 19 



