FRESH-WATER NEREIDS FROM THE PACIFIC COAST AND HAWAII. 211 



follow. The peristomal cirri are short, thick, and rapidly tapering to fine points. 

 They extend but little beyond the tips of the palpi when forwardly directed. The 

 basal joints are extremely thick and of considerable length. The tips of the dorsal 

 posterior pair are yellow. This is the only pigmentation in any part of the animal. 



The proboscis (PL XVII, Fig. 19) is divided, into the usual maxillary and basal 

 portions by a circular groove, but is entirely devoid of paragnaths, or even papillae 

 representing them. The jaws are of the usual form and possess seven teeth. 



The posterior extremity of the young specimen (99 somites) has a pygidium 

 a little shorter than the combined length of the two preceding somites, and no broader 

 than these. The anus is nearly terminal. The anal cirri are almost exactly the 

 same in shape as the dorsal cirri, and but little longer (PI. XVII, Fig. 18). 

 h The parapodia (PL XVII, Fig. 20), as in all species of Lycastis, are destitute of 

 ligules. The entire dorsal ramus is absent, the only indication of it being a dorsal 

 aciculum. The foot, therefore, is an example of extreme reduction in this genus. It 

 is approximately conical, with a retractile tip (PL XVII, Figs. 20, 21). This I believe 

 to be a characteristic feature of 1 the foot of Lycastis and Lycastoides. Although 

 figured by Gravier ('01, Figs. 2, 5, 7) for L. ouanaryensis, and apparently for L. 

 brevicornis by Audouin et Milne-Edwards ('32-'33) it has not been mentioned by 

 these authors nor by any others who have dealt with Lycastis. The dorsal cirrus, 

 conical in form and of moderate dimensions in the most anterior parapodia, attains 

 the length of the foot and seta? in the middle of the trunk and becomes thinner and 

 more lanceolate. In the posterior third (young specimen) it reaches beyond the tips 

 of the setae and exceeds the breadth of the trunk. The setse, 7 to 10 in number, are 

 inserted both above and below the ventral aciculum. Two or three are arastate * 

 (PL XVI, Fig. 11), are moderately heterogomph, slender, have long, slender, grad- 

 ually tapering, and finely serrate arista?, and are inserted above the aciculum. Stouter 

 setae with moderately long appendages (PL XVI, Fig. 12) are inserted between the 

 foregoing and the typical falcate seta? (PL XVI, Fig. 13). The two latter kinds are 

 extremely heterogomph, their appendages have a few coarse serrations and a wide 

 notch near the base, while their tips are smooth. The seta? exhibit a variety of color; 

 some are colorless and translucent, others nearly opaque and yellowish-brown of 

 different shades. The acicula are blunt at their distal ends, perfectly straight, and 

 diverge at a very narrow angle. They are black throughout nearly their entire length. 

 The presence of large ova in both adult specimens suggests that they breed where 

 found. This, however, is not necessarily the case, if the stations are easily accessible 

 from the sea. 



* I adopt the term arista to designate the elongated ("gratenformig") appendage of certain setse. 



