160 CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



Segmentation strongly accentuated, breadth of segments (in alcoholic 

 specimens) from two to three times their length. 



Head abruptly narrowed to the hoof-shaped prostomium, which is convex 

 above, but nearly flat beneath. On its ventral aspect is a slight longitudinal 

 groove which extends backward to the mouth. The prostomium bears two 

 pairs of cirri, a median cirrus or "tentacle," and two pairs of eyes; 

 the dorsal pair in front of the anterior pair of eyes, and same distance 

 apart as the latter; the ventral cirri further apart and in the same vertical 

 plane as the anterior pair of eyes. There is little or no difference in the 

 length of the paired cirri. 



Eyes four, the anterior pair considerably larger and a little nearer together 

 than the posterior; anterior pair placed in a transverse sulcus that divides 

 the dorsal side of the prostomium into anterior and posterior portions. The 

 posterior portion carries not only the four eyes, but also the tentacle, and ex- 

 tends caudad as the caruncle. Tentacle decidedly shorter than the paired 

 cirri, tapered uniformly from the base, and very acutely pointed at tip. 



Caruncle slender, cylindrical, flexuous, reaching anterior border of third 

 somite. 



Mouth triangular, the apex running forward as the median groove in the 

 ventral side of prostomium; bordered posteriorly by the fourth somite, 

 which forms a crenated and somewhat tumid lip. 



Anus terminal, minute. 



Parapodia (fig. 9) composed of two widely separated rami. The ventral 

 ramus with a fascicle of long, slender setae, of varying lengths, and a few short 

 hastate ones (figs. 12-14). The long seta have a slight lateral prong near tip; 

 they are silvery white by reflected light. The dorsal seta shorter than 

 the longest of the ventral fascicle, and of various lengths and sizes. They 

 fall under three types: (i)long, very slender, bifid setae, almost precisely simi- 

 lar to the corresponding type of the ventral ramus (fig. 12); (2) long, stout, 

 serrated setae (fig. 10); and (3) short and very stout, smooth seta? (fig. 11), 

 which probably correspond to the hastate seta? of the ventral ramus, but are 

 much more numerous. 



The dorsal ramus of every parapod, except the first, carries a ramose gill. 

 The number of branches in each gill increases backward ; the gills of the second 

 somite are very simple, having only two or three branches. The maximum 

 complexity is attained at about the twelfth somite. 



Dorsal and ventral cirri present on all the somites, very similar in form, 

 smooth, terete, jointed near base, evenly tapered to the small, rounded tip; 

 shorter than the longest seta; of both fascicles; dorsal cirrus considerably 

 longer than the gills. 



Number of somites, 60-93. 



Living color variable, flesh to dark brown. When sexually mature the eggs 

 shine through the body-wall and give the female a decided purple tinge, while 

 the ripe males are red. A beautiful purple and green iridescence on ventral 

 side. 



Measurements. — Length of full-grown specimen, 106 mm.; width, 5 mm.; 

 dorsoventral thickness, 3 mm. Length of smallest specimen (60 somites), 

 22 mm.; caruncle, 1 mm. long; average length of middle somites, 1.5 mm. 



