TREMATODES FROM FISHES — LINTON 



171 



DISTOMA species 



Plate 26, Figure 351 



Among the cysts containing larval distomes belonging to the genus 

 Eckinostoma^ from Percopsis omiscotnayGus^ collected at Constantia, 

 N. Y., Oneida Lake, June 6, 1915, two globular cysts, adhering to the 

 eyeball, contained immature distomes which are generically different 

 from the others. Measurements of one of the cysts, 0.66 by 0.57 mm. ; 

 the other, 0.45 mm. Measurements of distome, life : Length, 0.60 mm. ; 

 breadth, 0.60 mm. ; diameter of oral sucker, 0.13 mm. ; ventral sucker, 

 length, 0.13 mm., breadth, 0.16 mm. These distomes, mounted in 

 balsam, agree closely in their dimensions : Length, 0.53 mm. ; breadth, 

 0,53 mm.; oral sucker, length, 0.10 mm., breadth, 0.10 mm.; ventral 

 sucker, length, 0.14 mm., breadth, 0.18 mm. Measurements of distome 

 from cyst in liver, life : Length, 0.66 mm. ; breadth, 0.69 mm. ; diam- 

 eter of oral sucker, 0.14 mm.; ventral sucker, length, 0.18 mm., 

 breadth, 0.22 mm. But few details are shown in the balsam mounts. 

 They are smooth, nearly circular in outline, the cuticle very definitely 

 limited and firm ; ventral sucker larger than oral, broader than long, 

 its anterior edge at about middle of the length of the body; oral 

 sucker nearly circular. No pharynx or esophagus seen; intestinal 

 rami appear to be short and to have rather thick walls. There is a 

 deeply stained mass of cells between the ventral sucker and the pos- 

 terior end, not yet differentiated into genitalia. The parenchyma 

 throughout is finely and uniformly granular. (U.S.N.M. No. 8411.) 



ABBREVIATIONS USED ON PLATES 



a Acetabulum. 



c Cirrus. 



cp Cirrus pouch. 



exp Excretory pore. 



exv Excretory vessel. 



ej Ejaculatory duct. 



g Germinal pore. 



h Holdfast organ. 



i Intestine. 



I Laurer 's canal. 



Im Longitudinal muscle. 



m Metraterm. 



Ovary. 



o' Portion of ovary with mature 



cells. 



oe Esophagus. 



ph Pharynx. 



pr Prostate. 



sg Shell gland. 



sr Seminal receptacle. 



sv Seminal vesicle. 



sv' Second seminal vesicle. 



t Testis. 



u Uterus. 



vd Vas deferens. 



vg Vitelline gland. 



y Yolk reservoir. 



yd Yolk duct. 



Unless otherwise stated all sketches were made with the aid of the camera 

 lucida from balsam mounts. 



