186 
males were as follows; anterior testis 0,87 mm. long by 0,26 mm. wide; 
posterior testis, 1,05 mm. long by 0,26 mm. wide. The cement gland 
while containing eight nuclei as just described for N. gracilisentis differs 
radically from the cement gland of the latter species in that it is an 
extremely elongated organ with the nuclei arranged in a row down its 
central axis. Immature specimens present an early stage in the deve- 
lopment of this arrangement of the nuclei wherein the eight nuclei are 
arranged in two groups of four each. 
Females taken at a time just preceding the formation of the egg- 
masses have an unpaired elongated ovary 0,350 X 0,035 mm. in the 
posterior third of the body-cavity. Mature females are filled with em- 
bryos that are very minute. The dimensions 0,016 X 0,011 mm. are 
quite uniform, varying but two or three microns in large numbers of 
measurements. | 
Leidy has recorded this species as parasitic in the intestine of 
» Emys geographicus, Emys insculpta, Emys guttata, and Emys serrata<. 
The writer has found it of frequent occurrence in the intestine of 
Malacoclemmys geographicus (Le 8.) and of Pseudemys elegans Max. 
Nearly every turtle of the last two named species taken from the Illinois 
River and backwater lakes at Havana, Illinois, carried some of these 
parasites. The period of infestation has not been determined. Some 
interesting facts regarding the longevity of the members of this species 
have been gathered. A number of turtles for experimental purposes 
were placed in an aquarium in the month of October. These received 
no food whatever. The last of February of the following year one of 
these animals was examined and revealed an infestation of over seven 
hundred immature specimens of N. emydis (Leidy). Two months later 
another turtle was found to be the host of five Neorhynchi of the same 
species all of which had attained approximately the maximum body size 
for the species. The fact that there was no mixture of immature and 
mature forms in the same host would tend to indicate that during this 
period of starvation no new parasites were introduced into the intestine, 
probably explicable on the grounds that an intermediate host is required 
for the reinfestation of the final host, though the actual presence of 
such has never been demonstrated for any American species. These 
same facts seem to indicate beyond the possibility of a doubt that these 
parasites are capable of living entirely at the direct expense of the host, 
for during a period of six months these worms had not only continued 
to exist but had proceeded to develop into fully mature individuals 
when the host was undergoing starvation. No attempt has been made 
to estimate the influence of inanition of the host upon the length of 
time required for the parasites to attain sexual maturity. 
