GYCLOSTOMATOUS BRYOZOA CANU AND BASSLER. 



Ill 



basal lamella. The ovicell is irregular, not salient, placed at the 

 center of each subcolony. 

 Genotyj)e. — Alveolaria semiovata Busk, 1859. Plaisancian. 



ALVEOLARIA SEMIOVATA Bask. 1859. 



Plate 18, Figs, 1-i. 



1859. Alveolaria semiovata Busk, Monograph Fossil Polyzoa of the Crag, 

 Publications Paleontological Society, London, vol. 14, p. 128. 



Busk has very well described and figured the structure of this 

 genus and species and we here can only add some additional notes 



Fig. 31?. — Alveolaria semiovata Busk, 1859. 



A. Transverse section, X 16. 



B. Longitudinal section, X 16, through several subcolonies. 

 Pliocene (Plaisancian) : Sudbourne Church, Suffolk, England. 



from the study of thin sections. Each subcolony is a sort of bowl 

 covered exteriorly with a basal lamella (epitheca of D'Orbigny). 

 The tubes are cylindrical and adjacent on the entire length of their 

 concourse. They grow by dorsal gemmation in the vicinity of the 

 basal lamella and by peripheral budding in the middle of each sub- 

 colony. Diaphragms are present. 



