ECHIUROID FAUNA OF NORTH PACIFIC — FISHER 489 



distinction between the gizzard and the stomach (crop) , which ends 

 at the ring blood vessel. 



Vascular system : The vascular system differs sharply from that 

 of inamoenus and calif ornicus in having a clear-cut large ring vessel. 

 The dorsal blood vessel is voluminous ; its anterior part is held in place 

 by broad dorsal frenula which anchor the pharynx. Then follows a 

 free portion over the posterior part of pharynx-esophagus. Posterior 

 to this it is attached to the gizzard by a broad continuous mesentery, 

 from the front edge of which anchoring strands proceed forward to 

 surface of pharynx. Then posteriorly the dorsal vessel is attached to 

 wall of stomach, spiraling to right from the dorsal to ventral side, so 

 that the neurointestinal vessel enters the ring vessel dorsolaterally. 

 The interbasal muscle of setae passes through a loop of the neuroin- 

 testinal. 



Color in formalin, lavender-gray. 



Type.—V.S.'^M. No. 21098. 



Type-locality.— VwgQt Sound, Wash. (Normandy Beach, 12 miles 

 south of Seattle) , lower limits of a minus 2-foot tide, clam grounds, 

 May 22, 1948, 1 specimen, Sigurd J. Westrheim, collector. 



Re7narks.—Dv. J. E. Lynch, of the School of Fisheries, University 

 of Washington, who contributed the type specimen, states that to the 

 best of his knowledge this is the first adult echiuroid to be collected 

 in Puget Sound. 



The species is very distinct from calif ornicus and inamoenus in hav- 

 ing a direct connection between the dorsal and neurointestinal blood 

 vessels. A careful examination of the presiphonal gut of calif ornicus 

 did not reveal any ciliated groove. The material of this species is 

 in too poor condition to ascertain details of the intestinal fastening 

 muscles or frenula and hence whether the arrangement for the presi- 

 phonal gut of pugettensis is peculiar to the species. The details of 

 the mesentery of the dorsal blood vessel and the shorter lobes of the 

 nephrostomes appear to be of specific value. The great size of the 

 nephridia is probably due to their being packed with eggs, while the 

 disparity in size of the anal vesicles may be an abnormality. 



A. arhynchite (Ikeda) of Japan seems to have smaller skin glands 

 and to lack the large ring vessel, but details of the alimentary canal 

 are not available. 



Family BONELLIIDAE Baird 



In the construction of the following synopsis the first division 

 has been made according to the position of the nephrostome, whether 

 at base of nephridium, at its extreme tip, or placed laterally near the 

 distal end. As the outstanding structural peculiarity common to the 

 whole family, I think modifications of the nephridia contain the key 



