﻿SIPUNCULID WORMS OF CALIFORNIA — FISHER 431 



larger and slightly more protuberant and give a somewhat shaggy 

 appearance. The platelets of the papillae are less numerous and, 

 except near the center, are less crowded than in agassiyAi. Two ex- 

 amples from a small Panama specimen are shown on plate 36, figures 

 1 and 2. In the large specimen some of the papillae have the platelets 

 similar to figure 3 (agassiyAi) ; but more often they look like figure 3 

 with the smaller platelets removed, while the larger platelets have an 

 irregular, crenulated periphery. (See Selenka, 1883, pi. 9, fig. 137, 

 iiigrescens.) 



There are al)out 25 complete rings of hooks; anil back of these, 

 about 30 more dorsal half rings, with a few scattered hooks on the 

 ventral side of the introvert. In a Panama specimen (length 33 

 mm.) there are about 100 rings with a scattering of hooks beyond. 

 In adult agassi/Ai the hook rings seldom exceed 25 and are often 17 

 to 20, but in nigrescens the number varies from 30 to 120 (Selenka, 

 1883, p. 11). The hook of puntarenae (Selenka's pi. 1, figs. 1-3) is 

 very diff'erent from that of agassizii in the position of the clear streak 

 and in having a larger expanded portion of this streak. If the hook 

 were slightly more bent it would closely resemble that of nigrescens 

 (see pi. 39, fig. 2, and Selenka, 1883, pi. 9, figs. 130, 135). p:ven the 

 slight hump (a) characteristic of nigrescens is indicated in puntarenae. 



There are 24 tentacles surrounding the large heart-shaped nuchal 

 organ (pi. 39, fig. 3; compare pi. 36, fig. 4). The fold or ridge sur- 

 rounding the tentacles and mouth is colorless. Below this is the ring 

 collar immediately in front of the hook zone. 



The color is pale yellowish })rown, the trunk and dorsal side of 

 introvert irregularly peppered with dark bro\\Ti papillae. The hooks 

 form a brown zone behind the collar; then there is a dorsal half-ring 

 of dark brown, followed by 4 or 5 transverse dorsal bands of much 

 lighter reddish brown. The Guaymas specimen has a reddish brown 

 trimk without spots and about 10 dark-brown dorsal bands on introvert. 



In this typical section of the genus the internal anatomy does not 

 vary greatly from species to species. There are 20 to 30 longitudinal 

 muscle bands that anastomose freely, the lesser number being near the 

 front of the trunk. The ventral retractors have a broad base arising 

 from bands 2 to 7 on the right and 2 to 9 on the left. The fixing muscle 

 arises in the same place as in Fh. agassizii and its attachment to the 

 esophagus and to the rectum is the same. One point of difTerence is 

 the coecum, which is papilliform, several times longer than thick, and 

 relatively larger than in agassizii. A precisely similar coecum was 

 found hi a specimen of Ph. nigrescens from the Hawaiian Islands. The 

 reddish brown nephridia are larger than in any agassizii examined. 

 The proximal end is inflated. They reach nearly to the end of the 

 body, only the proximal third being anchored. The Hawaiian 



