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



posterior parapodia (Fig. 6). The dorsal cirrus remains large and moves out further 

 on the ligule. The number of setse in both rami diminishes greatly. 



The first and second parapodia have a well-developed dorsal ligule, but no dorsal 

 lip, setse, or aciculum. 



The setse are in nowise remarkable (PI. XVI, Figs. 7-10). The only form 

 worthy of special notice is the stout, falcate type in the ventral fascicles of the most 

 posterior parapodia, in which the appendage is firmly anchylosed to the shaft, the 

 whole forming one continuous piece (Fig. 10). 



I have not found Nereis limnicola generally distributed in Lake Merced. All 

 my specimens have been taken at the outlet of a "slough" on the eastern side of the 

 southern arm of the lake. At this point the shore is composed of a softer and finer 

 sand than usual, and in this sand the Nereis burrows to the depth of about eight 

 inches. It also lives in the moist sand of the shore under driftwood, much as earth- 

 worms frequent similar places. No tube is formed. If given a little sand in which 

 to burrow it stands confinement for weeks and even months. 



III. LYCASTIS HAWAIIENSIS sp. nov. 



The material at hand for the study of this interesting species consists of two 

 female adults, both of which lack the most posterior somites, and one young speci- 

 men. One of the adults and the young one were collected by Professor Miller in a 

 spring near Honolulu. The exact locality in the Hawaiian Islands where the other 

 adult was collected is not known. 



The form of the adult is long and slender, the larger specimen measuring 105 

 millimetres in length and 3.5 millimetres in greatest transverse diameter, including 

 parapodia. Its somites number over 190; a few of the most posterior are absent. 

 The young specimen has a length of 22 millimetres, a transverse diameter of 2 milli- 

 metres, and only 99 somites. Both adults carry nearly ripe eggs. The trunk of one 

 is so turgid as to be cylindrical; the other is considerably depressed, and the young 

 specimen still more so. 



The prostomium (PI, XVII, Figs. 17, 19,) is longitudinally divided by a 

 sharp median furrow, and is very broad in proportion to its length (2 : 1). The 

 antenna? are very short, thick, and horn-shaped; the palpi are extremely stout, with 

 spherical terminal articles. The eyes are placed far back on the prostomium, well 

 over towards its sides. The anterior pair are the larger, and a little further apart than 

 the posterior pair. The eyes of both pairs are destitute of lenses. 



The peristomium is as short as, or even shorter than, the somites that immediately 



