Helminth Fauna of the Dry Tortugas. 



33 



Helicometrina nimia gen. et sp. nov. (Figs. 40-48.) 

 I have adopted a suggestion made to me by Professor Pratt that 

 this form be placed in a new genus, but at the same time giving it a name 

 that would remind one of the genus Helicometra. 



Body oval, but assuming various contraction shapes, fusiform, pyri- 

 form, etc., slightly nodular on head and neck; ventral sucker about 1.5 

 times the diameter of the oral sucker; neck one-third or more the length 

 of the body. There is a short prepharynx and the pharynx is longer 

 than broad; esophagus relatively long; genital aperture median, just 

 behind the bifurcation of the intestine; cirrus-pouch clavatc, inclosing 

 the tubular and convoluted seminal vesicle in its basal portion. The 

 cirrus-pouch may be wholly median, its base slightly overlapping the 

 anterior edge of the ventral sucker, or the base may lie along the antero- 

 lateral margin of the ventral sucker either on the right or the left side. 

 The prostate is represented by a few cells in the anterior portion of the 

 cirrus-pouch. Testes normally 9, usually in two longitudinal rows, one 

 row on each side of the median line in the posterior part of the body, 

 5 testes on the right side and 4 on the left. A few variations from this 

 order are noted below. Ovary median, ventral, and much lobed, in part, 

 at least, between the two anterior testes. A yolk-reservoir lies dorsal and 

 a little in front of the ovary, and a seminal receptacle on its right anterior 

 border. The vitelline glands are diffuse and lateral from the posterior 

 end to the bifurcation of the intestine, or a little in front of that point. 

 The wreathed folds of the uterus lie between the ovary and the ventral 

 sucker. The ova are filamented. The excretory vessel is not distinct 

 in the mounted specimens, but was noted in the living specimens as a 

 conspicuous median vessel extending from the posterior end, where it 

 may be greatly inflated, along the median line as far as the ovary. 



While the testes are usually arranged in two longitudinal rows, 5 on 

 the right side and 4 on the left, one was noted with 4 on the right side 

 and 5 on the left (44c). Another was seen with 4 on the right and 5 on 

 the left, the extra testis being at the level of the second where there were 

 2 transversely placed instead of 1 (446). A similar doubling was noted 

 in another, where the last two testes on the right side were transversely 

 placed (44(f) . 



Dimensions of specimens mounted in balsam. 



The cirrus-pouch was on the right side of the ventral sucker in 4, on 

 the left side in 1, median in 5, right central in 1, and right median in 1. 

 3 



