22 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 14 



Membranipora villosa Hincks, 1880 

 Plate 1, figs. 10 and 11 



Membranipora villosa Hincks, 1880a:84. 

 Membranipora villosa, Robertson, 1908:268. 

 Membraniporavillosa^O'Donoghnt, 1923:26; 1926:29; 1926:250. 



The zoarium is encrusting, especially on the larger kelps, the colonies 

 often coalescing to cover considerable areas. The zooecia are of moderate 

 size, thin-walled; the gymnocyst is wanting or limited to the proximal 

 corners ; the cryptocyst narrow proximally and laterally, finely crenulate 

 and often with a few minute spinules; the opesia occupying practically 

 all of the front. A characteristic feature is the chitinous spinules ; minute 

 spinules arise on the frontal membrane almost anywhere except on the 

 operculum ; slightly larger ones, often nearly as long as the width of the 

 zooecium, arise just within the lateral margins; a still larger and heavier 

 spine is located at each proximal corner, and one still larger, 0.50 mm or 

 more is frequently found in a median position. All of these spines are 

 elongate-acuminate, the basal ones sometimes forked, and without calci- 

 fication except the bases of the larger ones in the proximal corners. 



The development of this species has been well discussed by Robert- 

 son (1908:269-275) and O'Donoghue ( 1926a :249-261). There is a 

 twin ancestrula, the earlier zooecia are somewhat hexagonal in form, 

 but the later zooecia are elongate-quadrilateral much like those of M. 

 membranacea and the spinules are less marked, often nearly wanting on 

 the later zooecia. 



Hincks described the species from California; Robertson listed it 

 from Puget Sound to San Diego, California, and O'Donoghue from 

 numerous British Columbia localities. 



It did not occur in the Hancock dredgings but it is abundant on the 

 kelps all along the California coast. 



Membranipora serrilamella new name 

 Plate 1, figs. 12 and 13 



Membranipora membranacea form serrata Hincks, 1882:469. 



Membranipora serrata, Robertson, 1908:268. 



Membranipora serrata, O'Donoghue, 1923:26; 1926:29. 



Conopeum serrata, Okada, 1929 :1 1. 



Membranipora serrata, Okada, 1934:4. 



Acanthodesia serrata, Marcus, 1937 :44. 



{^ot Membranipora serrata MacGillivray, 1868:6). 



