NO. 1 OSBURN : EASTERN PACIFIC BRYOZOA CHEILOSTOMATA 45 



Hincks described the species from Santa Cruz, California, and 

 O'Donoghue lists triangulate from "Gabriola Pass; Brotchie Ledge, 

 Victoria, B.C." 



Hancock Stations: 1187-40 and 1325-41, off Santa Catalina Island, 

 1269-41, Anacapa Island, California; 2167, Dewey Channel off Point 

 San Eugenio, and 2168, Cabeza Ballena, Lower California, and 431-35, 

 off Octavia Rocks, Colombia. The known range is therefore from British 

 Columbia to Colombia, and down to 60 fms. 



Hincksina pallida (Hincks), 1884 

 Plate 23, fig. 2 



Membranipora pallida Hincks, 1884:39. 

 Membranipora acifcra form multispinata Hincks, 1884:8. 

 Membranipora pallida, O'Donoghue, 1923 :25. 

 Hincksina pallida, O'Donoghue, 1926 :3 1 . 



Zoarium loosely attached by dorsal processes, thin. Zooecia elongate, 

 elliptical, length 0.60 to 0.70 mm, width 0.25 to 0.30 mm; gjminocyst and 

 cryptocyst vestigial ; the walls thin and smooth, beset with 5 to 8 slender, 

 pointed spines which bend somewhat over the opesia, except the most 

 distal pair which are erect. Avicularia appear at the base of many of the 

 zooecia, the chamber more or less quadrate, the mandible broad at the 

 base and tapering rapidly into a very long acicular point; at first glance 

 the avicularia appear to be mounted on the zooecial base, but their mode 

 of development shows them to be interzooecial, and the extent of their 

 chambers can readily be seen on the dorsal side. The mandibles average 

 0.35 mm in length, with a strongly decurved tip. 



The ooecia are endozooecial, low and inconspicuous, cucullate with a 

 wide aperture, 0.18 mm wide by 0.10 mm long. 



Hincks first considered this to be a form of M. acifera MacGillivray, 

 but later described it as a new species; his discussion and figure (pi. 19, 

 fig. 4) are good but he did not have the ovicell and did not discuss the 

 nature of the avicularian chamber (Virago Sound, British Columbia). 

 O'Donoghue discovered the ovicell and removed the species to Hincksina 

 (a number of localities in British Columbia, the San Juan Islands north- 

 ward). Neither Hincks nor O'Donoghue mentions the peculiar mode of 

 attachment which is by means of a short chitinous tube growing from the 

 middle of the dorsal side of many of the zooecia. 



Hancock collections, — a number of colonies dredged near Friday 

 Harbor, Puget Sound, Dr. J. L. Mohr, collector. 



