316 ORDER ANAXONCHIA 



lowish granules of variable size, arranged irregularly. The posterior lip of the 

 anus is slightly raised. Rectum only about two-thirds as long as the anal body- 

 diameter. The tail is conoid in such fashion that, at a distance from the anus 

 equal to eight times the anal body-diameter, it has a diameter about one-fourth 

 as great as at the anus. The remainder of the tail has been lost from the speci- 

 men from which the description was drawn and is therefore of unknown form; 

 hence the dimensions given in the formula must be interpreted accordingly. The 

 tail is just as distinctly striated as the body. -The lateral fields are about one- 

 third as wide as the body. It is probable that the renette is located at a distance 

 behind the base of the neck about equal to two body-diameters. At this point 

 there is an elongated structure somewhat longer than the body is wide and about 

 one-fifth as wide as it is long, which bears a general resemblance to a renette 

 cell. From the slightly elevated vulva, the vagina extends inward and forward. 

 The tapering ovary ends somewhat in front of the cardia where it is about one- 

 fourth as wide as the corresponding portion of the neck. The eggs are about 

 three times as long as the body is wide, and about one-fourth as wide as long. 

 There is a small posterior rudimentary branch to the sexual organs, extending 

 back from the vulva a distance equal to two to three body-diameters. This 

 has been seen to contain spermatozoa and may function as a spermatheca. The 

 presence of caudal glands remains problematical. Unfortunately, also, in the 

 case of the only male specimen available, the tail is broken, but that portion of 

 it remaining is about two-thirds as long as the neck. It tapers a little more 

 rapidly at first than it does farther back, in fact, toward the terminus, it must 

 be very nearly cylindroid. It seems probable that caudal glands are present, 

 but there is some doubt about this. There are no special supplements, papillae 

 or setae on the male. The long and slender hairs found on the body occur also 

 on the tail, and are there equally long and slender so far as observed. The 

 proximal ends of the acute, slender spicula present the peculiarity of being 

 separated from the remainder of the spicula by straight shafts, having a length 

 somewhat greater than that of the cephalic portions. The cephalic portion, 

 together with this shaft constitutes about one-fourth of the spiculum; the remain- 

 ing portion of the spiculum is uniformly arcuate, and tapers regularly to the sub- 

 acute terminus. The proximal ends of the spicula lie toward the dorsal side of 

 the body. There are inconspicuous accessory pieces arranged parallel to and 

 close by the spicula, and which are about half as long as these latter. The ejacu- 

 latory duct is one-third, and the vas deferens about one-half, as wide as the body. 

 Development of the spermatozoa in the two testes presents rather marked con- 

 trasts. From the blind end of the anterior testis, lying near the base of the neck, 

 the spermatozoa develop regularly and form spermatocytes half as wide as the 

 body, which develop into spermatozoa with nuclei that stain prominently. The 

 blind end of the posterior testis contains spermatocytes which, for a short dist- 

 ance, resemble those already described, but they do not form large spermato- 

 cytes. They nevertheless develop into spermatozoa having the character just 

 described. At a distance in front of the anus about equal to the length of the 

 tail, there are three glands on each side of the body, arranged tandem. These 

 glands are accessory to the male organs. Each is more or less homogeneous ante- 

 riorly, and granular posteriorly, the granules not retaining carmine stain, as do 

 the nucleus and the anterior parts. The ducts of these glands lead backward to 

 the cloaca. 



Habitat: Mud, tide pool, near low tide mark, Portsmouth, New Hampshire, 

 U. S. A. Fig. 97, p. 315. 



