36 



ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 14 



Dr. Borg discusses six varieties, all but one of which were once con- 

 sidered species and in several of these the median proximal spine and the 

 calcification of the operculum are wanting. Our specimens resemble the 

 variety baltica in general appearance, but in the lack of the proximal 

 spine and in the very weak calcification of the operculum they suggest 

 the variety stammeri (See Plate 3, fig. 5). 



Hancock Station 1478-42, Yaquina Bay, Oregon, on shells along 

 shore. The species has also been taken at Dillon Beach, and Monterey 

 Bay, California, 



Electra crustulenta var. arctica Borg, 1931 



Plate 3, fig. 4 



This well-marked variety, characterized by a single strong spine in 



the midline proximal to the opesia, is abundant at Point Barrow, Alaska, 



G. E. MacGinitie, collector; at Punuk Island, Bering Sea; Nunivak 



Island, Nash Harbor, Alaska and south to Dillon Beach, California. 



( Electra anomala new species 



Plate 3, fig. 6 



Zoarium encrusting, thin and delicate. The zooecia are moderate in 

 size, averaging about 0.50 mm in length by 0.30 mm in width, but there 

 is a wide range in both dimensions; distinct with deep separating grooves; 

 walls thin, the mural rim narrow and somewhat inflected, smooth or 

 slightly granular. The gymnocyst is variable from one-fourth the zooeci- 

 al length to almost wanting ; cryptocyst not evident. The opesia is ellipti- 

 cal, narrowed at the base of the operculum, which is well chitinized. 

 From the middle of the front surface of the operculum arises a pair of 

 very elongate, bifurcate chitinous spines which extend far over the base 

 of the distal zooecium ; this anomalous condition is without parallel in the 

 writer's experience. 



At the distal end, on either side, is a short, stout, erect spine, which 

 often appears to belong to the distal zooecium. The marginal spines are 

 extremely variable; in the same colony the zooecia of the central area 

 for several generations are spineless ; there follows a narrow transitional 

 zone in which there are a few spines, increasing in size and number out- 

 ward ; and finally a climax is reached with 8 to 10 long, slender spines 

 on each side which bend low across the opesia until their points may 

 pass each other; frequently these are briefly bifurcate at their tips, but 

 there never appears to be any fusion of the tips. No avicularia; no ooecia; 

 multiporous septulae are present in both lateral and distal walls. 



