﻿SIPUNCULID WORMS OF CALIFORNIA — ^FISHER 387 



at the base, on the incurved side, a comb of curved booklets that are 

 transparent, but brownish, hke the hook. Tlic liook rings are in 

 tiny furrows separated by glandular ridges. The glands are immersed 

 in the skin, 0.08 to 0.09 mm. by 0.04 to 0.05 mm., placed close together 

 (the shorter diameter transverse), and each has a definite pore near 

 the next aboral hook ring, 0.015 mm. in diameter. 



The body is covered with spaced, small, mammiform glands sur- 

 mounted by a more or less evident cylindrical papilla. In the type, 

 probably caused by preservation, these are involved in transverse 

 and longitudinal folds of the skin. These gradually decrease in size 

 forward on introvert, where the skin folds become closely placed 

 rings on which the glands, now tiny conical papillae, are borne. 



The longitudinal muscles of the body wall in 20 to 26 rather broad 

 bands, close together, flat when the body wall is inflated, and only 

 occasionally anastomosing. These bands extend in front of the 

 anus for a distance about half that between the anus and the posterior 

 extremity, and forward of this the inner muscle layer is continuous, 

 transversely crinkled like silk. The circular muscle layer is thin and 

 not separated into bundles. Integumentary pockets absent. The 

 retractor muscles are very slender; ventrals arising far forward, at 

 about one-fifth the distance between the anus and end of the body, 

 from muscle bundles 3 and 4 ; dorsals arising between anus and nephrid- 

 iopores from muscles 2-3 left, 3 right, or 1-3 both sides (type). 

 Forward of the nephridium, the dorsals and ventrals unite into a single 

 muscle on each side of the slender esophagus. Spindle muscle starts 

 forward of anus and follows usual course, but is not attached poste- 

 riorly; the two lateral roots, usually present in Siphonosoma, are 

 absent. Fixing muscle F anchors ascending intestine to muscle 

 bundle 1 left. 



The nephridia are reddish brown, with a prominent anterior lobe, 

 which may be short or long (up to one-third to one-half length of 

 posterior lobe). The anterior lobe is sometimes turned posteriorly. 

 Nephrostome: the lower part of the lip is attached to the body wall, 

 the free part having slender lobes. The nepliridium is attached 

 obliquely for a short distance at base, and opens between muscles 

 4 and 5, or through a cleft on 4. No Keferstein bodies. 



The esophagus is very slender, without fixing muscle. Intestinal 

 spiral with about 20 double coils; a conspicuous coecum on rectum. 

 The contractile vessel is very slender and without diverticula. The 

 nerve cord in the anterior part of the introvert has a mesentery; 

 farther back it is free except for the moorings by the lateral nerves. 

 The gonad is at the origin of the ventral retractors. 



Type. — U.S.N.M. No. 21224, from under boulders along with 

 Phascolosoma antillarum and Ph. puntarenae, March 20, 1940, E. F. 

 Ricketts collector, 22specimens. 



969586—52 2 



