232 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 



Genus PETALOSTEGUS Levinsen, 1909 



The membranous frontal area is covered by a circle of mutually 

 connected platelike or leaf -like hollow spines; a slightly chitinous, 

 semicircular simple operculum. The avicularia are sessile. The 

 zooecia are in one row (Levinsen, 1909). 



Genotype. — Petalostegus (Catenaria) bicornis Busk, 1884. Recent. 



Fig. 93. — Genus Cornucopina Levinsen, 1909 



A-E. Cornucopina grandis Busk, 1852. A. Two zooecia showing a finely 

 dentated cryptocyst, X40. The zooecia are very asymmetrical, from the nar- 

 row tubelike proximal part widening into an obliquely funnel shaped extremity. 

 B. The same zooecia from the basal surface. The radical fibers, which go 

 down along the basal surfaces of the colony, are issued from a septula a good 

 ways f list ally on the basal aspect of the zooecia, X40. C. A zooecium with a 

 large avicularium, X40. D. The frontal surface of the avicularium, X40. 

 E. The avicularian mandible, X55. 



F-I. Cornucopina infundibulata Busk, 1885. F-H. A zooecium with ovicell 

 in three different positions; the distal wall is seen in G and H, X23. The ovieclls 

 are placed on zooecia of ordinary size. I. A sagittal section through the same 

 ovicell bearing zooecium; it shows that the ovicell is surrounded by a kenozooe- 

 ium, X23. (Figs. A.-I. Alter Levinsen, 1909.) 



Family BEANIIDAE Canu and Bassler, 1927 



No ovicell; the larva develops in the interior of the female zooecia 

 in which the polypide is small. The zooecia are little calcified and 

 are joined together by stoloniform prolongations containing a multi- 

 porous septule. Often there are pedunculate avicularia. The dorsal 

 frequently bears large radicells with multifid base. The colonies 

 are unilamellar, uni or multiserial. 



