NO. 2 OSBURN: eastern pacific BRYOZOA — CHEILOSTOMATA 411 



moderate (one-third the width of the aperture). The secondary aper- 

 ture is irregularly pyriform, the peristome with a low lappet on each 

 side and proximally it embraces the transverse avicularium in an unsym- 

 metrical notch ; it is wanting distally where 2 small evanescent spines 

 are rarely present. The suboral avicularium is median in character though 

 sometimes slightly at one side of the midline ; the elongate curved rostrum 

 often makes it appear assymmetrical when the chamber is median ; the 

 mandible is ogival or triangular in form, the tip strongly decurved ; the 

 avicularian chamber is not prominent. 



The ovicell is rounded or slightly elongate, 0.20 to 0.24 mm wide; 

 a broad collar surrounds the base leaving a central rounded area on the 

 top which is perforated by numerous small pores. 



The type of suboral avicularium is unusual. Busk described the species 

 from Australia (Challenger Sta. 163a) and it does not appear to have 

 been noticed since. 



Hancock Station 1344-41, south of San Nicholas Island, southern 

 California, 32°53'00"N, 119°23'45"W, one colony at 75 fms. 



Genus PARASMITTINA, new genus 



Avicularia variously distributed on the frontal, but never median, 

 suboral and bilaterally symmetrically developed around the proximal 

 border of the aperture ; they take their origin from areolar pores on one 

 side. The frontal is a pleurocyst with a row of areolar pores and occa- 

 sionally there are some additional pores, usually at the proximal end ; 

 the lyrula and cardelles usually well developed, though the overhanging 

 peristome in some cases may require dissection to expose them. The ovicell 

 is variously perforated, by numerous small pores, by several larger ones 

 which may vary in size and form, or more rarely by 1 to 3 central pores. 

 Genotype, Lepralia Jeffrey si Norman, 1876:208. 



The essential differences between this group and Smittina (sens sir.) 

 are in the nature of the frontal and the avicularia. The frontal is a 

 pleurocyst, and even in the occasional zooecia which have additional pores 

 inside from the areolar row the pleurocystal layer is seen to develop 

 from the border toward the center; young marginal zooecia show this 

 manner of growth, especially after incineration. The avicularia are vari- 

 ous in size, form and distribution, but the chamber is never bilateral ; 

 they may be oval, spatulate, short-triangular or long-pointed and range 

 from minute to gigantic, and they may sometimes be interzooecial ; not 

 infrequently there may be several forms and sizes on a single zooecium ; 

 they often vary greatly on the same zoarium. 



