coe: nemerteans of west and northwest coasts. 287 



Habitat. — Dredged in about 50 fms. between San Pedro and 

 Santa Catalina Island, California, associated with Taeniosoma 

 punnetti and Carinella albocincta. Not common. One specimen 

 was dredged by the Albatross off southern California (Sta. 2946, 

 Lat. 33° 58' N., Long. 119° 30' W.) at a depth of 150 fms. Bottom 

 of coarse gray sand ; temperature 56° F. 



Tetrasterama Ehrenberg. 

 Symbolae Physicae, Berlin, 1831. 



This genus includes a group of very small, slender worms, seldom 

 more than 20 to 30 mm. long, with slightly flattened body, and 

 usually Avith four well developed ocelli, which form a qxiadrangle 

 on the head. In a few species (cf. 2\ aberrans) these ocelli are 

 each replaced by a groixp of two or three smaller ones, and in other 

 species ocelli are wanting entirely. The anatomical structures are 

 very similar to those of Amphiporus, and the distinctions between 

 the two genera are not clearly defined. Mouth and proboscis open 

 together. Cerebral sense organs lie close in front of brain. Pro- 

 boscis sheath extends to posterior end of body and is without lateral 

 diverticula ; proboscis is well developed, armed with central stylet 

 and usually two pouches of accessory stylets ; it is usually provided 

 with ten nerves. 



Ten species of this common and widely distributed genus have 

 now been collected on the Pacific coast of North America, and are 

 enumerated below. Of these ten species only one {T. dorsale) has 

 been recorded from other parts of the world. One form ( T. albi- 

 dum) is here described as new. 



75. Tetrastemma signifer Coe. 



Harriman Alaska Expedition, U, p. 156, PI. 14, figs. 9-11 ; PI. 21, 



figs. 10-12, 1904. 



PI. 2, fig. 24 ; Text-figs. 21, 56. 



This pretty little species with its dainty cephalic marking exhibits 

 the following peculiarities of appearance and structure : — 



Body rather slender, rounded throughout, not veiy changeable in 



