276 University of California Publications in Zoology. [Vol. 4 



what obliquely, mandible directed upward. Ooecia subimmersed, 

 large, minutely punctate, sometimes possessing a slight projection 

 in front. 



The avieularia are rarely present, and the thickened extremi- 

 ties of the margins which in some cases are said to be prominent 

 tuberosities, do not acquire a great size in the specimens exam- 

 ined. The ooecia are perhaps more deeply immersed than is 

 shown in the drawing. 



Micropora coriacea was obtained on the west side of the island 

 of Santa Catalina, dredged at 45 fathoms. 



Steganoporellidae Hincks. 



Steganoporellid(e Hincks, 1887. 



ZooEcia closed by a membranous wall which carries the orifice 

 and operculum ; divided by a horizontal calcareous lamina or 

 cryptocyst into two compartments, in the lower of which the poly- 

 pide is lodged ; at the distal or oral end of each zooecium a large 

 variously shaped opening. 



Thalamoporella Hincks. 



TJialamoporella, Hincks, 1887, vol. 19, p. 164. 



Zooecia in which the lower compartment contains a flask or 

 vase-shaped chamber formed by the cryptocyst, in which the 

 polypide resides and through whose narroAv neck it protrudes 

 when expanded; on each side of the neck a lateral cavity or 

 foramen ; covered only by the membranous front wall. Orifice 

 large, only partially closed by the operculum. Operculum small, 

 semi-circular. Ooecia external, bilobate. 



Thalamoporella, and at least one other genus of this family 

 viz., Steganoporella, are characterized by the possession of a well 

 developed cryptocyst. The term cryptocyst is applied to the 

 calcareous wall of the zooecium which forms a layer more or less 

 parallel with the chitinous ectocyst, the outermost layer of the 

 zooecium. The cryptocyst in the genus Thalamoporella, is not 

 complete. In the proximal part of the zooecium it extends from 

 one lateral margin to the other, but as it approaches the oper- 

 culum it contracts, its lateral edges bend downward, thus pro- 

 ducing a narrow neck (pi. 17, fig. 28, nl-;.), through which the 



