TRISSONCHULUS 



297 



m(3J.....lb(6) 



X. Order Aponchia. 



78. Trissonchulus oceanus n. sp. Cuticle naked, practically without marks of 

 any kind. Onchia refractive, in contour roughly equilateral, slightly curved, 

 apparently with an outward stroke. When the mouth is slightly open, the apices 

 of the teeth are on a level with the surface of the head. Neck slightly conoid, 

 convex-conoid at the head. Amphids very faint. Inner surface of each of the 

 six lips armed with scores of exceedingly minute, closely set denticles. Oesoph- 

 agus cylindroid, then conoid in the posterior fourth, where there is a faint cardiac 

 swelling, which can hardly be called a bulb. At the nerve-ring the oesophagus is 

 one-half, and finally three-fifths, as wide as the corresponding part of the neck. 

 The indistinct lining is expressed by three parallel 

 lines occupying a space two-sevenths as wide as 

 the oesophagus. There is a conoid cardia one-half 

 as wide as the base of the neck. The thin-walled 

 intestine becomes at once three-fourths as wide as 

 the body, at least when gorged. Its cross-section 

 is probably made up of eight to ten cells. These 

 cells contain scattered colorless granules of vari- 

 able size, the largest of which are one-fortieth as 

 wide as the body. Tail sub-cylindroid in the ante- 

 rior three-fourths. The spinneret presents the 

 peculiarity of being on the ventral surface of the 

 tail some distance from the tip. (See illustra- 

 tion.) The elongated-ellipsoidal caudal glands, 

 as long as the body is wide and one-third as wide 

 as long, are located in front of the copulatory mus- 

 cles. They form a loose tandem, and empty 

 through distinct ducts and ampullae, the latter 

 being large and filling the tail. There are no cau- 

 dal setae. The lateral fields are one-third as wide 

 as the body and contain large, ellipsoidal cells 

 nearly as wide as the fields themselves, occurring 

 at intervals of one to three body-widths; these are 

 apparently glandular, and connect with the sur- 

 face by means of pores on the lateral line. The 

 excretory pore is at the lips and is directed for- 

 ward. The renette cell, one neck-length behind 

 the cardia, and as long as the neck, is granular and 



contains a large nucleus; its duct is about as wide \ *1 H '"' fe -^'* > 3.6 



as the cuticle is thick, and being coarsely granular, 



is rather easily followed. There is an anterior rudimentary part to the female 

 sexual organs two to three body-widths long. From the continuous vulva, the 

 medium-sized, more or less tubular vagina leads inward two-fifths the distance 

 across the body. The broad, cylindroid ovary contains about thirty ova, 

 arranged single file proximally, but irregularly distally. Tail of the male smaller 

 and more arcuate than that of the female, and more nearly conoid. The proximal 

 ends of the stoutish, tapering, rather blunt spicula appear to lie opposite the 

 body-axis. There is a rather frail, slender accessory piece. There is a low and 

 more or less obscure ventral pre-anal elevation at the anterior portion of the 

 region occupied by the copulatory muscles. This may perhaps partake of the 

 nature of a supplementary organ. On each side, in front of the anus, there are 



X750 



