﻿SIPUNCULID WORMS OF CALIFORNIA — FISHER 377 



and Anaheim Slough, in southern California, were colonized by an 

 off-shore population, as was the Estero de Punta Banda, south of 

 Ensenada. Professor MacGinitie took it also at a lagoon, Alu-amar 

 Beach, Guaymas, Mexico, while Ricketts established a record at 

 La Paz. 



Specimens examined. — Thirty-five, as follows: 



Guaymas, Mexico, lagoon at Miramar Beach, Feb. 9, 1948, G. E. MacGinitie, 



1 specimen. 

 El Mogote, Baja California, near La Paz, March 22, 1940, E. F. Ricketts, 1 



specimen. 

 Estero de Punta Banda, Baja California, 6 miles south of Ensenada, Dec. 19, 1930, 



sand, G. E. MacGinitie, 5 specimens. 

 Anaheim Landing, Calif., March 1918, gravel, 2 specimens. 



Newport Bay, Calif., January to February 1930, G. E. MacGinitie, 20 specimens. 

 Pacific Grove, Calif., Jan. 6, 1939, washed ashore by high seas, 6 specimens. 



Genus XENOSIPHON Fisher 



Xenosipkon Fishek, 1947, p. 360. (Type, Sipunculus branchiatus W. Fischer.) 



Diagnosis. — Differing from Sipunculus sensu stricto in the following 

 particulars: Integumental coelomic spaces in the form of independent 

 sacs of irregular outline; an extra pair of muscles functioning as 

 retractors and protractors arising from posterior border of introvert 

 and inserted in front of brain; rectum unusually long, the anus being 

 in front of nephridiopores ; postesophageal intestine without a long 

 forward loop; nephridia long, slender, attached to body wall for 

 nearly their entire length; squamiform papillae of very short introvert 

 increasing in size toward the tentacles, which have very many leaflets 

 arranged in sub triangular pads surrounding the mouth; type species 

 with papUliform dermal outgrowths. 



XENOSIPHON BRANCHIATUM (Fischer) 



Plate 19 



Sipunculus mundanus var. branchiatus W. Fischer, 1895, p. 3, pi. 1, figs. 1, la, 2. 

 Sipunculus branchiatus Spengel, 1913, p. 74. 

 Xenosiphon branchiatum Fisher, 1947, p. 360, pi. 12. 



Description. — The following description is based chiefly on three 

 specimens from Panama. Length 310 mm.; introvert and tentacle 

 crown 20-25 mm.; thickness of cylindrical body 8-12 mm., this 

 varying according to constriction of ring muscles. The specimen from 

 La Paz, 420 mm. long, is constricted in the middle of body to 8 mm. 

 diameter. Longitudinal muscle bands 29-34, only rarely anasto- 

 mosing. When the body is fully inflated the longitudinal and circular 

 muscles divide the surface into flat rectangular areas separated by 

 rather inconspicuous grooves, but when constriction takes place there 

 is apparent a series of more or less convex annuli. The middle third 

 of the body, except for a ventral zone, about six muscle bands in width, 



