48 NORTH AMERICAN 



a third at the base of the pharynx on the dorsal side. The oesophagus be- 

 gins as a tube about half as wide as the corresponding portion of the neck, 

 and continues to have this diameter until it swells to form the pyriform 

 cardiac bulb, which is about three-fourths as wide as the base of the neck, 

 and contains a distinct chitinized threefold, rather simple, valvular apparatus, 

 occupying two-fifths of the diameter as seen in longitudinal section. The 

 musculature of the bulb is divided into three sections, a small anterior sec- 

 tion, a middle and a posterior section. Of these two latter the posterior is 

 slightly the smaller. The lining of the oesophagus is a fairly distinct feature 

 throughout its length. There is no very distinct cardia. The intestine joins 

 the middle of the posterior surface of the cardiac bulb, and is there one- 

 fourth as wide as the base of the neck. It soon expands so as to become 

 about two-thirds as wide as the body. It is rather thick walled, and is com- 

 posed of rather thick cells which are of such a size that about four are re- 

 quired to build a circumference. These cells contain minute granules. From 

 the anus the rectum, which is considerably longer than the anal body diam- 

 eter, extends inward and forward. The tail is conoid, and tapers from the 

 anus toward the terminus, which is conoid and has a diameter one-third as 

 great as that of the base of the tail, and bears a blunt convex-conoid unarmed 

 spinneret. The rather small caudal glands appear to be located in the an- 

 terior third of the tail. The lateral fields have not been seen. From the 

 inconspicuous vulva the vagina leads inward at right angles to the ventral 

 surface to the single or double uterus, which when single extends forward. 

 There sometimes appears to be a small posterior rudimentary branch to the 

 sexual organs, which is about equal in length to the corresponding body 

 diameter. The reflexed ovary reaches about halfway back to the vulva, 

 and contains about half a dozen or more ova arranged somewhat irregu- 

 larly. The eggs appear in the uterus one at a time. They are smooth, some- 

 what thin-shelled, and are about twice as long as the body is wide, and about 

 one-third as wide as long. They appear to be deposited before segmentation 

 begins. Specimens with one ovary, and those with two, appear to be about 

 equally numerous ; as no other difference has been detected, they are in- 

 cluded for the present under the same name and description. The renette 

 cell is an elongated cell located a short distance behind the base of the neck. 

 It is fully as long as the body is wide, and about one-fourth as wide as the 

 body. The excretory pore appears to be located opposite the nerve-ring. 

 The nerve-ring surrounds the oesophagus somewhat squarely. 

 Habitat: Maple River, Michigan. Sublimate to balsam. 



TRIPYLA, Bastian, 1865. 

 Fig. 7, Plate III. 



49, 



--,.,, LI 6.8 19.6 '54' 83.5 



7. Tnpyla lata, n.sp. 2.4 mm. 



2.3 3-1 3-5 4- 3-2 



The thick layers of the transparent, colorless, naked cuticle are apparently 

 traversed by about 250 transverse striae, which are not further re- 



