NO. 3 OSBURN : EASTERN PACIFIC BRYOZOA — CYCLOSTOMATA 621 



Again there is but little difference in the nature of the ovicells. The 

 fertile zooecium arises like any other tubule and is narrow at its proximal 

 end, broadens to various degrees in the different species, and terminates 

 in a slightly elevated and more or less terminal ooeciostome. The terminal 

 expansion of the gonozoid misled Canu and Bassler into believing that 

 the enlargement was a part of the peristome, and on this basis they 

 created a genus Peristomoecia which has since been discarded. 



The genus also has a close relationship to Oncousoecia Canu and 

 Bassler (q. v.), which similarly has simple ovicells of much the same 

 nature, but has a flabellate zoarium. 



Whatever may be the ultimate disposition of these three groups of 

 species, it seems better for the present to allow them generic status — 

 for convenience in classification if for no better reason! 



Large numbers of "species" have been created on incomplete material, 

 probably most often on immature specimens. It is practically useless to 

 attempt to identify such specimens since only the mature ones with the 

 characters of the ovicells show specific characters. 



Proboscina major (Johnston), 1847 

 Plate 65, fig. 5 



Alecto major Johnston, 1847:281. 



Alecto major. Busk, 1875:24. 



Stomatopora major, Hincks, 1880:427; 1884:204. 



Stomatopora major, O'Donoghue, 1923:11. 



Diaperoecia major, O'Donoghue, 1926:23. 



Oncousoecia major, Canu and Bassler, 1930:46. 



The zoarium is adnate, strap-shaped, the branches narrow and widen- 

 ing slightly, sometimes a little elevated at the tips on rough substrata. 

 Zooecia in two to four series, the tubules distinct with well-marked 

 grooves, and sometimes in more or less transverse rows; the peristomes 

 moderately high, free, with round apertures. The diameter of the aper- 

 ture varies greatly, from 0.14 to 0.20 mm and the peristome likewise 

 from 0.20 to 0.26 mm on the same colony. 



The ovicells are located near the ends of the branches or just proximal 

 to a bifurcation. The narrow proximal end is comparatively short; the 

 middle portion expanded and rather bulbous; the ooeciostome sub- 

 terminal, erect, rather short, smaller than the peristome, its aperture 

 about 0.12 mm in diameter. Usually the inflated area is simple in form, 

 but it may be slightly lobed between the surrounding zooecial peristomes, 

 and occasionally a peristome may be surrounded. 



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