450 



BULLETIN 100, UNITED STATES NATIONAL MUSEUM 



are separated by a narrow longitudinal ridge in the central line. A 

 little proximally to the aperture we find a median pore surrounded 

 by a ring which is continuous with the longitudinal ridge. The 



A H 



Fig. L82- Genus Cribricellina Canu and Bassler, 1927 



A ('<. Cribricellina riifa MacGillivray, 1SGS. A. General aspect, frontal and 

 basal, of the branches. B. Lateral view of the zooecia. The small .suprascapular 

 chamber, (lie greatly bent infrascapular chamber and the slightly bent pedal 

 chamber are seen ; X/35. C. A zooeeium from the basal surface. The suprascap- 

 ular and the infrascapular chambers are seen and less distinctly the pedal, X55. 

 D. A terminal gonozooecium, X40. E. Lateral view of (hegonozooecium, X40. 

 F. A sagittal section of a gonozooecium, X23. G. A portion of the sternal area 

 from the internal surface. The cryptocyst plate is seen, X 100. 



H-K. Cribricellina cribruriaTiWRk, 1852. H. General aspect, frontal and basal, 

 of the branches. (A, H. After MacGillivray.) I. Lateral view of a zooeeium, 

 X55. J. Basal surface of a zooeeium, X55. K. A portion of the external area 

 from the internal surface. The cryptocyst plate is seen, X 100. (B-G, I-K, after 

 Levinsen. 1909.) 



aperture is provided with well developed distinct hinge-teeth and has 

 a proximal concave margin. 



Genotype. — Strophipora (Catenicella) harveyi W. Thompson. 1858. 



Range. — Miocene of Australia. Recent. 



In this gentis are included the three following subgenera of Mac- 

 Gillivray which differ only in secondary characters. 



Subgenus Microstomarm MacGillivray, 1895. The zooecin are 

 small. The apertura is small, nearly circular and projecting forward. 

 Example: Microstoma ria tuhdifera MacGillivray, 1895, from the 

 Mioeene of Australia. 



