280 University of California Publications in Zoology. [Vol.4 

 49. Cribrilina hippocrepis Hincks. 



PI. 18, fig. 31. 



Cribrilina hippocrepis Hincks, 1882, vol. 10, p. 470, pi. 20, figs. 



6, 6a. 

 Cribrilina annulata, Eobertson, 1900, p. 326. 



Zoarium incrusting shells, worm tubes, etc. Zooecia irreg- 

 ularly alternate, oblong; front wall calcareous, slightly convex, 

 punctured by lines of pores lying in shallow grooves between the 

 radiating ridges (pi. 18, fig. 31) ; first row of pores immediately 

 below the orifice extending usually across the zocpcium from side 

 to side ; the remaining rows, five in number, as a rule, radiating 

 from a point midway between the lower margins of the oper- 

 culum and the base of the zooecium. At the origin of each ridge, 

 near the margin, a rather large pore. Orifice well arched above, 

 constricted a little above the lower margin which is straight; 

 closed by a dark chitinous operculum, op. Avicularia, av., large, 

 as long as a zooecium, but narrower, and occupying the place of 

 one; surrounded by a calcareous margin, mandible acutely point- 

 ed and directed upward or outward toward the distal edge of the 

 colony. Ooecia globose, of medium size, punctured with a few 

 large pores. 



Cribrilina hippocrepis is reported by Hincks from Queen 

 Charlotte Islands. That observer found no ooecia in the speci- 

 mens examined by him, but these structures were obtained in ma- 

 terial dredged at San Pedro. This species occurs at Yakutat, 

 Alaska, and at San Pedro and Coronados Islands, California. 



Microporellidae Hincks. 



Celleporidce (part) Johnston, 1847. 

 Memhraniporidce (part). Busk, 1854. 

 Foridm (part) d'Orbigny, 1850-52. 

 EscJiariporidcB Smitt, 1867. 

 MicroporellidiB Hincks, 1880. 



Zooecia adnate, incrusting, or forming erect and foliated or 

 dendroid zoaria; orifice more or less semi-circular, with the lower 

 margin entire; a semilunar or semi-circular pore on the front 

 wall. 



