252 



ORDER CYTOLAIMIA 



32o. Rhabdocoma americanum n. sp. Type species. Cuticle thin, naked except 

 for the cephalic setae. Lips three. Wall to the pharyngeal cavity in optical 

 section showing three somewhat thickened elements, that are possibly minutely 

 transversely ribbed; these elements, however, are very smallfand difficult of 



resolution. Neck somewhat conoid 

 anteriorly. Oesophagus at the 

 nerve-ring two-fifths, at the cardia 

 two-thirds, as wide as the corre- 

 , spending portion of the neck, and 

 containing glands, as is indicated 

 by fine granular matter in branched 

 dettUtfh . U trm -^ ff W/ X750 cavities. Cardia more or less 



spheroidal, one-half as wide as the base of the neck. The rather thick-walled 

 intestine presents a faint lumen and becomes at once about one-half as wide as 

 the body; its cross-section presents but few cells. Anus continuous; rectum 

 about as long as the anal body-diameter. The intestinal cells contain granules 

 of variable diameter, the largest one-tenth as wide as the body. Doubly refrac- 

 tive granules occur in all parts of the intestine, but are not numerous; these tend 

 to have quadrate contours and do not present St. Andrew's crosses. The tail 

 tapers very gradually throughout, commencing well in front of the anus. Ren- 

 ette unknown. There is an anterior rudimentary branch to the female sexual 

 organ, about as long as the body is wide. From the rather large, more or less 

 depressed vulva the well-developed cutinized vagina extends inward three-fifths 

 the distance across the body. The elongated eggs are twice as long as the body 

 is wide. The broad, cylindroid ovary reaches three-fourths the distance back 

 to the vulva and contains very many ova, those of the two-thirds next the uterus 

 being arranged single file. The frail spicula are about one and two-thirds times 

 as long as the anal body diameter and are rather wide apart. Accessory pieces 

 faint. Supplements papilloid, twelve to sixteen, occupying a distance in front 

 of the anus ten to twelve times as long as the body-diameter, while a second 

 series of about eight, occurs on the neck. The members of the anal series are 

 somewhat farther apart anteriorly; of the cervical series, posteriorly. 

 Habitat: Sand among mussels, Devil's Island, Woods Hole, Mass. Fig. 32. 



6. Rhabdocoma macrurum n. sp. L J -3 i.* %-^i.j " Very closely 



resembles the preceding, but differs in the following respects: straight setae, 

 nearly as long as the head is wide, digitate, with a minute setose mucro; amphids 

 a trifle farther forward, somewhat elongated; apparently four, submedian, min- 

 ute, short setae opposite the posterior margin of the amphids; accessory pieces 

 one-half as long as the spicula and parallel to them. 



Habitat: Sulphurous sand, Bay of Naples, toward Vesuvius, 1888. 



.35 2.6 7.6 l -44-" 81. 



33. Didelta maculatum n. sp. h* L5 J - 8 1>2 * " Cuticle, which is 

 above medium thickness and naked except for the setae on the head, is charac- 

 terized by the presence of peculiar transversely-elongated refractive subcuticular 



