﻿SIPUNCULID WORMS OF CALIFORNIA — ^FISHER 435 



Diagnosis. — Habit robust; trunk brown from numerous low convex 

 papillae, large and crowded at posterior end and in anal region; intro- 

 vert abruptly cream color, only about one-tliii'd trunlv length; no 

 hooks; tentacles long, very numerous; superficially resembling Den- 

 drostomum. Length, including tentacular cro^vn, 57 mm.; trunk, to 

 anus, 37 mm.; anus to cephalic collar, 16 mm.; width of tenacular 

 crown, 10 mm. 



Description. — ^Selenka gives the number of tentacles 50 to 80 ; in my 

 specimen there are nearer 200, pale cream coloj' (as is most of introvert) 

 with only an indication of brown spotting near the tips. The ex- 

 panded tentacidar disk, to accommodate the large number of its 

 peripheral tentacles, is thrown into regular folds (pi. 39, fig. 9) as 

 happens in fully expanded sea anemones having a large number of 

 tentacles. The form of the centrally located nuchal organ is shown in 

 this figure. The mouth is overhung by the tentacles. Directly below 

 it the cephalic collar has a slight projection on its otherwise even edge. 



The skin of the trunk is divided into subquadrate areas by fmTOws. 

 In each area is a deep-bro\\Ti convex subcu-cular papilla composed of 

 numerous closely placed chitinous platelets, while between these 

 closely spaced papillae the cream-colored skin contains separated 

 dark-brown platelets. The ventral papillae are slightly larger than 

 the dorsal; in most species of the genus the reverse is true. At each 

 end of the trunk the papillae are much larger than elsewhere. At the 

 posterior end and on the ventral side of the anal region, the whole of 

 each papilla area becomes filled with densely crowded brown platelets. 

 Dorsall}^ in the anal region the large papillae are slightly separated 

 and often of irregular form. Abruptly, just in front of the anus, the 

 papillae become much smaller, elongate conical, sharp, and decrease 

 in size toward the second collar. 



The muscle bundles of the mncr layer anastomose. There are 

 about 20 in the anterior part of the trunlv and 28 to 30 posteriorly. 

 Dorsal retractors arise only a short distance in front of the ventrals 

 at the beginning of the posterior third of the trunk. The two muscles 

 of each side soon unite. In a strongly contracted specimen there is 

 hardly any separation and the animal appears to have only two 

 retractors arising near the posterior end of the body. The degree of 

 separation is like that of Phascolosoma asser (Selenka, 1883, fig. 97). 

 There is one fixmg muscle arising on the left of the nerve cord in 

 about the same place as in agassizii. It is attached to the rectum in 

 front of the coecum and some of its fibers pass into the spindle muscle. 

 At the point of its attachment to the rectum a part of the muscle 

 continues and is attached to the esophagus as it forms the first coil. 



The contractile vessel carries very numerous conspicuous slender 

 villi, which extend from just behind the head to the first coil of the 



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