462 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 



Genus ONCHOPORA Busk, 1852 



The colonies are hi or quadriserial. The operculum is simple. 

 The ovicell has a couple of proximal, free, rib-like processes. At 

 least 6 apertural septulae of which two small ones are between the 

 ascopore and the apertura. 



Genotype. — Onchopora sinclairi Busk, 1852. Recent. Onchopora 

 picoensis Jullien 1903 and Onchopora grimaldi Jullien, 1903 (which we 

 figure), belong to another genus, according to Levinsen, 1909. 



Fig. 194.— Genus Calwellia W. Thompson, 1858 



A-C. Calwellia bicornis W. Thompson, 1858. A. The one-half of the distal 

 wall of the lowermost pair of zooecia is seen and also two of the internal oval 

 septulae through which the stalk-like proximal end of a pair of zooecia is in 

 communication with the wider distal part of another pair; X40. B. A trans- 

 verse section through a branch; between the stalk-like proximal part and the 

 wider distal part. A pair of zooecia is seen from the distal end, and also the 

 forked distal walls and four intersected stalklike proximal parts; X55. C. A 

 transverse section through a branch approximately through the middle of the 

 wider distal part of a pair of zooecia; X55. (A-C After Levinsen, 1909.) 



D, E. Calwellia gracilis Maplestone, 1882. D. Young zooecium and parts of 

 its neighbors. E. Two mature zooecia, sho^ ing the large compensation sacs 

 (c. s); c. p. communication pores (septulae); prox. the narrow pioximal part of a 

 distal zooecium; occl., occlusor muscles of operculum; m. p., median pore; op., 

 operculum; s., suture in calcareous wall;/., membraneous fenestra. (D. E. After 

 Harmer, 1902.) 



Genus CALWELLIA W. Thompson, 1858 



The zooecia horn-shaped and provided with a narrow caudal por- 

 tion are joined together back to back with perpendicular pairs between 

 them. 



Genotype. — Calwellia bicornis W. Thompson, 1858. Recent. 



