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



Professor Miller's note as regards the color states that they are "flesh-color, 

 changing to green in formalin." The living coloration is evidently due to the blood, 

 the peripheral vascular system being very richly branched. Without the blood the 

 worm would be colorless or white. 



L. hawaiiensis is evidently most nearly allied to those species of the genus with 

 extremely reduced dorsal rami, short tentacular cirri, and much enlarged foliaceous 

 dorsal cirri. Perhaps it comes nearest to L. ouanaryensis of French Guiana (Gravier, 

 :01) and to L. senegalensis (Saint-Joseph, :01). It differs sufficiently from both of 

 these to require the establishment of a new species. 



An interesting feature in Lycastis hawaiiensis is the penetration of the peripheral 

 blood-vessels into the epidermis until they actually come into contact with the 

 cuticula (PL XVII, Fig. 22, vessels solid black; Fig. 23). In this species the vascular 

 loops in the dorsal cirri are exceedingly numerous and near together, as may be seen 

 in a young specimen cleared with glycerine, and as appears in a section taken 

 parallel with the flat surface of the cirrus (Fig. 23). These cirri, therefore, like the 

 broad dorsal ligules of Nereis virens, function as gills; and it is to secure better 

 aeration for the blood that the vessels have penetrated the thick epidermis. 



IV. LYCASTOIDES ALTICOLA gen. nov., sp. nov. 



The species from the Sierra Laguna, Lower California, presents such an exactly 

 intermediate condition between Ceratocephale (Malmgren, '67) and Lycastis that it 

 is impossible to say to which it is the more nearly allied. It is therefore necessary 

 to establish a separate genus for it. Roughly speaking, this genus may be said to 

 have the prostomium of Ceratocephale and the foot of Lycastis. The single specimen 

 available for study exhibits one character so aberrant, not alone for a nereid but 

 for any polychsete (although we see it slightly developed in the Polynoidse and in 

 Chrysopetalum) that I am tempted to regard it as an abnormality. I refer to the 

 greatly elongated common basal joint of the posterior pair of peristomial cirri (PL 

 XVII, Fig. 24, right side). On the left the shorter ventral cirrus of this pair is 

 wanting. 



The prostomium (PL XVII, Fig. 24) is bilobed by a deep median sulcus. Ante- 

 riorly these lobes pass insensibly into the antennae, just as in Ceratocephale. There 

 are no eyes. The palpi are short and globose, their terminal articles almost com- 

 pletely retracted. The peristomium is large as compared with the prostomium, 

 and the latter is partially hooded by it a feature more fully developed in Nereis 

 cyclurus of Puget Sound (Harrington, '98; Johnson, :01). The peristomial cirri are 



