240 University of California Publications in Zoology. [Vol. 6 



Zoarial branching' in this species is fairly regular. As has 

 been said, seven is the characteristic number of zocecia in an 

 internode, with a branch arising from the third zocecium. "When 

 there are more than seven zocecia in an internode, there will 

 usually be more than one branch in that internode, or if but 

 him branch it will occur higher up than the third zocecium. e.g., 

 on the fifth. C. occidentalis is dioecious. Ocecial colonies never 

 produce testes. Male colonies are abundant and never produce 

 ovicells. The branches of male colonies characteristically close 

 their growth at the distal end with a long spinous process. Such 

 colonies do not present the curled appearance of ocecial colonies, 

 so that the practiced eye soon detects the difference between them 

 even when no ovicells are visiMe. 



This species was formerly regarded as identical with C. 

 eburnea. In some respects it shows relationship with both C. 

 eburnea and G. denticulata. Although both species have been 

 reported from this coast, a study of typical C. eburnea and ('. 

 ih nticulata, and a careful comparison with this species shows 

 marked differences especially in the ovieell and its aperture, and 

 in the branching of the ocecial internode. C. m < /</< ntalis shows 

 some resemblance to C. sinclairensis Busk ('75) but Busk says 

 nothing of the ovieell, and identification is impossible. The 

 present identification is made not so much upon the description 

 and figure furnished by Trask, as upon the fact that it has been 

 obtained in great abundance in the type locality, viz., San 

 Francisco Bay, where it is the only biserial species of Crisia 

 found. 



C. occidentalis is abundant between tide marks at Lands End and 

 Fort Point, San Francisco; in smaller quantity at low tide on Deadmans 

 Island, San Pedro; between tide marks at Mendocino City and at 

 Navarro, California; obtained also in small quantity at San Juan County, 

 Washington. Dredged in ten fathoms off Santa Cruz Lighthouse; dredged 

 also off San Pedro in from 2 to 6 fathoms of water. 



88. Crisia operculata sp. nov. 



PI. 19, figs. 13, 14, 15. 

 Zoaria composed of delicate, brittle, straggling tufts from 12 

 to 20 mm. in height, attached by hairlike, flexible rootlets. 

 Tnternodes of a varying number of zocecia: the lower intemodes 



