402 



TRICOMA AND OTHER NEW NEMATODE GENERA, 



-M 85-3 



1-8 3- 



3-3 



•8 mm. 



consist largely, if not exclusively, of diatoms, several species of 

 diatom-shells being nearly always discoverable in the digestive 

 canal. The rectum is equal in length, in the female, to the anal 

 body-diameter. The elongated post-cardiac ventral gland empties 

 its excretion through a ventral pore situated opposite the lateral 

 organs. The tail is conoid from the depressed anus ; the secretion 

 of the caudal glands finds exit at the slightly expanded naked 

 and apiculate terminus. The depressed vulva leads to a vagina 

 one-half as long as the body is wide. The uterus rarely contains 

 more than a single egg, — unsegmented, — about as long as the 

 body is wide and one-half as wide as long. The blind end of the 

 ovary lies about as far behind the cardiac constriction as the 

 nerve-ring is in front of it. 



The tail of the male is precisely like 

 that of the female, if 

 we except its tendency 

 to be ventrally arcuate. 

 The two equal linear 

 almost uniformly arcu- 

 ate spicula, twice as 

 long as the anal body- 

 diameter, are of uniform 

 size, the proximse being 

 remarkable, not on 

 account of any expan- 

 sion or contraction as 

 is often the case, but on 

 account of the rather 

 sudden straightening of 

 those parts of the spi- 

 cula ; finally it is to be 

 noticed that the middle 

 parts of the spicula are 

 situated well toward 

 the dorsal side of the body. The accessory pieces are one-fourth 

 as long as the spicula, and when seen in profile are somewhat 



Fig. 8. — Monhystera diplops. 

 I, male worm. II, and 



IV, head and anal region of 

 the same worm more highly 

 magnified. Ill, portion of 

 the body of a female, sho-tting 

 the vulva. 



a, lip. 



b, cephalic seta. 



c, pharynx. 



d, eye. 



e, lateral organ. 

 /, nerve-ring. 



g, excretory pore. 



h, ampulla. 



i, posterior end oesophagus. 



j, cardia. 



k, ventral gland. 



I, blind end of testicle. 



m, egg. 



n, intestine. 



0, 0, 0. diatoms in intestine. 



p, vulva. 



q, junction of vas deferens 

 and ejaculatory duct. 



r, one of the caudal glands. 



s, ejaculatory duct. 



t, proximal end left spiculum. 



u, posterior part of ejacula- 

 tory duct. 



V, shaft, left spiculum. 

 w, rectum. 



X, anus. 



y, accessory piece. 



z, terminus. 



