82 PEOCEEDINGS OP THE ISTATIOITAL MUSEUM vol.72 



Affinities.— This species resembles very much Petraliella chuakensis 

 Waters, 1913, and we at first identified it so. However, it differs in 

 its much smaller micrometric measurements (la = 0.25 mm. and not 

 0.32 mm.), in the presence of two small apertural avicularia, in the 

 occurrence of a thread separating the cells, in the presence of short 

 interareolar costules, and in the much more finely denticulated prox- 

 imal border of the aperture. It resembles also Petraliella dorsiporosa 

 Busk, 1884, figured by Harmer, 1900, but differs from it in a much 

 larger zooecial avicularium, in the presence of interareolar costules, 

 in the serrate proximal border of the aperture, and in a single cribri- 

 form area to each zooecium on the inner face. 



Biology. — Our specimens were in reproduction and fixation Jan- 

 uary 30 and March 19, 1885. 

 Occurrence. — Albatross Station D. 2366, Gulf of Mexico, off Yuca- 

 tan; 22° 28' 00'' N.; 87° 02' 00" W.; 43m. 

 Albatross Station D. 2405, Gulf of Mexico; 28° 45' 

 00" N.; 85° 02' 00" W.; 30 fms.; gray sand, broken 

 coral. 

 Albatross Station D. 2414, Gulf of Mexico; 25° 04' 

 30" N.; 82° 59' 15" W.; 26 fms.; fine white sand, 

 broken shells. 

 Cotypes.— Cat. No. 7569, U.S.N.M. 



Genus COLEOPORA Canu and Bassler, 1927 



COLEOPORA GRANULOSA, new species 



Plate 33, Figure 9 



Description. — The zoarium is incrusting. The zooecia are large, 

 distinct, separated by a very thin thread, somewhat elongated, swol- 

 len; the frontal is convex and formed of a granular tremocyst; the 

 peristomie is salient, free, cylindrical; the peristome is thin. The 

 aperture is suborbicular. 



,, ^ A ^ f/ia = 0.20 mm. 



Measurements. — Aperture , „ „ ^ 



^ [?a = 0.25mm. 



fX2 = 1.15-1.25 mm. 



Zooecial 7 _ „^ _ „_ 



Us = 0.75 -0.85 mm. 



Aijinities. — The peristome shows distinctly the tremocyst and the 

 subadjacent olocyst; on certain cells the tremocyst overlaps the olo- 

 cyst and on others the olocyst is visible. 



This species approaches very closely Coleoporo. minutipora Canu 

 and Bassler from the Philippines, but its micrometric dimensions are 

 much smaller and its frontal granules are larger and more apparent. 

 The genus Coleopora is equatorial. It is probable that it is represented 

 in the Gulf of Mexico. 



Occurrence. — Pliocene: Minnitimmi Creek, Bocas Island, Almirante 

 Bay, Panama. 



Eolotype.—C&t. No. 70834, U.S.N.M. 



