104 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 14 



process. Avicularia wanting, Ovicells entozooecial, large. Communica- 

 tion-plates uniporous septula." Genotype, Eschara denticulata MacGilli- 

 vray, 1868. 



Harmer places the genus "in the Membraniporine series" apparently 

 allying it to Acanthodesia, and Silen (1929:134) appears to agree with 

 this arrangement. Canu and Bassler (1929:134) assign it to the Opesi- 

 uHdae, assuming that the anterior process of the cryptocyst is an in- 

 complete polypide tube. It certainly has this appearance since it is trans- 

 versely convex and flared upward at the tip. The large endozooecial 

 ovicell would seem to remove the genus from any close association with 

 Acanthodesia. 



^f Caleschara mexicana new species 

 Plate 11, fig. 11 



Zoarium encrusting in a thin layer, flat and white. Zooecia of moder- 

 ate size (0.40 to 0.50 mm long by about 0.26 mm wide), separated by 

 very narrow shallow grooves, the sides nearly parallel. The mural rim is 

 thin, regularly beaded ; gymnocyst not evident ; the cryptocyst is coarsely 

 granulated and fills the proximal half of the front, extending narrowly 

 around the distal border of the aperture. The anterior process of the 

 cryptocyst extends nearly to the aperture, transversely convex (like the 

 roof of a polypidian tube), the tip elevated and somewhat spatulate and 

 bordered by numerous lateral spinules which give it a slightly fimbriate 

 appearance. The opesiules are open, elongate and somewhat slit-like, the 

 outer border crenulate and often with a few spinules ; usually there is a 

 pair of larger spinules in the position of cardelles. At each proximal 

 comer of the cryptocyst there is a smooth, shining, subglobular tubercle, 

 occasionally wanting on one or both sides. No avicularia; no dietellae, 

 and in our specimens no ooecia have been observed. 



This species appears to be rather close to C. levinseni Harmer (1926: 

 221) but that species is evidently larger (Harmer merely states "zooecia 

 large") and appears to lack the horizontal spinules of the process and 

 opesular borders. 



Type, AHF no. 28. 



Type locality, Mazatlan, Mexico, 23°09'N, 106°23'W, shore col- 

 lection, 4 colonies encrusting the smooth surfaces of shells. (Miss A. E. 

 Blagg, collector.) Also from Panama, Galtsofl collection, Sta. 23, several 

 colonies covering the whole inside of a pearl oyster shell, an area about 

 75 mm in either direction. 



