98 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 14 



Genus TREMOGASTERINA Canu, 1911 



The ovicell is hyperstomial and closed by the operculum. The aper- 

 ture bears two small cardelles; the operculum, often chitinized, is at- 

 tached to the ectocyst. The frontal is a pericyst extending over the ecto- 

 cyst or frontal membrane ; the central area is perforated by 2 or 3 large 

 reniform or rounded pores. Large avicularia arise from the lateral walls 

 and assume an interzooecial appearance. Genotype, T. problematica Canu, 

 1911. 



Tremogasterina granulata var. subspatulata new variety 

 Plate 10, fig. 8 



Zoarium encrusting, usually on sponges, usually unlaminar, white to 

 light yellow in color, often covering several square inches. 



Zooecia ventricose, distinct with deep separating grooves in the young 

 stage, but becoming nearly level with increased calcification. On both 

 sides and around the proximal end there is a row of rather large rounded 

 pores, resembling the areolar pores of the Ascophora, and from the distal 

 pore on one side arises the avicularian chamber ; with increased calcifica- 

 tion the frontal outlets of the pores of neighboring zooecia usually unite 

 so that there seems to be but one row, a fact which no doubt explains 

 the statement of Canu and Bassler (1929:119) in regard to T. celle- 

 poroides (Busk) that "there is only a single range (of pores) between 

 two adjacent zooecia." In balsam mounts of marginal zooecia the two 

 rows are very distinct in the youngest zooecia and in older ones the 

 separate pores may be seen at the bottom of the single opening. Even the 

 secondary pores often become completely closed ofiE in older zooecia. 



The frontal is a pericyst, above the frontal membrane, and appears 

 to be formed in a different manner than any other pericyst. Acicular 

 spicules are laid down inside from the zooecial walls, at first conforming 

 to the "areolae," then becoming concentric about the central pores, while 

 more distally they conform to the aperture and even extend around it on 

 the distal border. When first formed this layer is thin and smooth, but 

 it very soon becomes heavily calcified and much roughened, and the fur- 

 rows between the zooecia are filled ; the depression about the central pores 

 remains evident at all stages. The whole process resembles the formation 

 of the olocyst and pleurocyst of the Ascophora, as first stated by Canu 

 and Bassler (1928:44) and later (1929:117) corrected by them. 



The aperture is somewhat quadrate, the sides straight, the distal end 

 rounded, the proximal end slightly arcuate and broader, length 0.22 to 

 0.26 mm, width 0.18 to 0.20 mm; peristome low and very thin with 2 



