378 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 14 



Microporella ciliata stellata (Verrill), 1875 



Porellina stellata Verrill, 1875 :53. 



Microporella ciliata var. stellata, Osburn, 1912 :234. 



Microporella ciliata var. stellata, O'Donoghue, 1923 :30. 



Similar in all respects to M. ciliata except that the ascopore is not 

 provided with a calcified shelf but with minute spicules all around the 

 border which give the pore a stellate appearance. Occasionally a small 

 shelf is present, similar to that of ciliata but smaller. 



Described by Verrill from Casco Bay, Maine, and found commonly 

 by Osburn in the Woods Hole region of Massachusetts. O'Donoghue 

 records it from British Columbia. 



Hancock collections : specimens with the stellate pore and with inter- 

 mediate conditions from Mussel Point, Dillon Beach and Monterey 

 Bay, California. 



Microporella umbonata (Hincks), 1884 

 Plate 44, fig. 4 



Microporella ciliata form umbonata Hincks, 1884:15. 

 Microporella ciliata va.r. umbonata, O'Donoghue, 1923 :31. 

 Microporella umbonata, Canu and Bassler, 1923 :123. 



The general characters of this form are much like those of ciliata, 

 but in its complete calcification it presents a very striking appearance 

 with high pointed umbos on the front and the ovicell and on each side 

 of the aperture. The zooecia are slightly larger than those of ciliata, 

 very heavily calcified, the gibbous frontal comparatively smooth except 

 for the median umbo, the tremopores large and numerous. The aper- 

 ture is more elongate than in ciliata, forming more than a semicircle, 

 the proximal border straight, cardelles not evident. The peristome is 

 low and thin, with 4 to 6 small oral spines which are evanescent. The 

 ascopore is of moderate size, semilunar, close to the border of the aper- 

 ture and usually obscured by the median umbo. There is a single 

 avicularium, often wanting, situated as in ciliata at one side proximal 

 to the ascopore and oriented diagonally. 



The ovicell is large, 0.28 to 0.33 mm wide, heavily calcified, per- 

 forated like the frontal, with a large blunt or pointed umbo on the top. 



The lateral umbos are usually tipped forward as in Hincks' figure 1 

 (plate 17), but occasionally stand erect beside the aperture. 



Described by Hincks from Dolomite Narrows, British Columbia; 

 listed by O'Donoghue without data, and recorded by Canu and Bassler 



