492 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 14 



Family Gelleporidae Busk, 1852 



The zooecia are usually erect and irregularly disposed though at the 

 growing edge they may be horizontal and oriented. Ordinarily the zooecia 

 are heaped upon each other in irregular layers and turned in all direc- 

 tions in the most irregular manner. The ooecia are recumbent on the 

 distal surface of the peristome, and they vary greatly in details in the 

 different genera. Oral avicularia are present in most of the genera in 

 various positions and often elevated. Frontal and vicarious avicularia 

 of various shapes and sizes are often present. 



Waters (1913:510) subdivided the family on the basis of the form 

 of the aperture into schizostomatous (with a sinus) and holostomatous 

 (without a sinus) groups, and Canu and Bassler (1920:596) added a 

 third group with a clithridate (keyhole-shaped) aperture. The family 

 is a large one, numerously represented, found in all seas, and is difficult 

 of study since the primary characters are usually obscured. 



Key to the Genera of Celleporidae 



1. Aperture with a straight or broadly arcuate proximal border, with- 



out a sinus but an irregular notch may sometimes be present . 2 

 Aperture with a more or less definite median sinus in the proximal 

 border 3 



2. Ovicell an open hood, imperforate Holoporella 



Ovicell cover complete, except for a central pore which may be 



closed in final calcification Trematooecia 



3. Peristome high, with a small avicularium on each side ; ovicell with 



a perforated area above the orifice Costazia 



A single avicularium on a rostral projection proximal to the aper- 

 ture ; ovicell perforated but without a special frontal 

 area Schizmopora 



Genus SCHIZMOPORA MacGillivray, 1888 



Cellepores in which the proximal lip of the aperture bears an arcuate 

 sinus and the ovicell is complete and perforated with evenly distributed 

 pores. The small oral avicularia are situated on the disto-mesial side of 

 an asymmetrical umbonate process which is sometimes much elevated; 

 the frontal avicularia are usually large and spatulate, often sparsely dis- 



