NO. 2 OSBURN: eastern pacific BRYOZOA CHEILOSTOMATA 305 



Family StOmachetOSellidae Canu and Bassler, 1917 



Frontal wall a very thick tremocyst or pleurocyst, built up around 

 the aperture and notched to form a spiramen which is sometimes guarded 

 by small avicularia. Primary aperture simple, without lyrula and usually 

 without cardelles. Ovicell hyperstomial, deeply embedded. 



The original description of the family has had to be modified to 

 include other genera than Stomachetosella which have been assigned to 

 this family. 



The genera here treated may be distinguished by the following key: 



1. Frontal a tremocyst with wide-mouthed pores 2 



Frontal a pleurocyst with areolar pores only 3 



2. Proximal border of the aperture with a sinus . . Stomachetosella 

 Proximal border of the aperture without a sinus . . . Pachyegis 



3. Zoarium with cylindrical branched stems, zooecia on all 



sides Diatosula 



Zoarium encrusting or erect with flattened bilaminate lobes or 

 frills 4 



4. Zoarium erect from a small base, branching in lobes or pal- 



mate Ragionula 



Encrusting base usually wide, the erect portion, often wanting, 

 forming broad bilaminate frills Posterula 



Genus STOMACHETOSELLA Canu and Bassler, 1917 



"The ovicell entirely surrounds the aperture. The frontal is a tremo- 

 cyst with wide-mouthed tubules. No avicularia. The peristomice of the 

 ovicelled zooecia possesses a straighter rimule-spiramen." (Canu and 

 Bassler, 1917:45.) Genotype, Stomachetosella crassicollis Canu and 

 Bassler, 1917:45. 



The ovicell is hyperstomial but is deeply submerged in the base of 

 the succeeding zooecium. The ovicell does not "entirely surround the 

 apertura," instead a thick rim of the frontal wall surrounds the aperture 

 on the sides and connects or fuses with the edges of the ovicell. 



Key to Species of Stomachetosella 



1. Ovicell wanting cruenta 



Ovicells present 2 



2. Ovicell imperforate 3 



Ovicell with one or more pores 4 



