FAMILIES AND GENERA OF THE MADREPORARIA. 155 



produce lobes or collines at the articular surface. Synapticula 

 exist. 



Distribution. — Fossil. Cretaceous : Europe. Eocene : Europe, 

 Asia. 



G-enus Ckateroseris, Tomes, Quart. Journ. Geol. Soc. 

 vol. xxxix. p. 560 (1883). 



Oorallum composite, massive, depressed turbinate; calicular 

 surface superior and convex. There is a common wall which is 

 naked and costulated. The calicos are evenly distributed, round 

 and prominent, but depressed in the middle ; and they have a 

 well-defined fossula. The intercalicular spaces are depressed. 

 The septa are imperforate ; margins moniliform and continuous 

 with septo-costae, which pass from one calice to another without 

 interruption. Septa and septo-costa have sjriiapticula attached 

 to them. Increase by gemmation between the calicos at the outer 

 margin. 



Distribution. — - Fossil. Portland Oolite : England. 



No section is given of this form ; and in the description of 

 the species the synapticula are said to be rather small. 



There is some doubt about the next genus, and regarding its 

 proper alliance. M. de Fromentel notices (' Introd. a I'etude,' 

 p. 241) a species of a genus called Thamnoseris which had been 

 communicated to him by Etallou ; and this author remarks on M. 

 de Fromentel, and gives a correct generic diagnosis of the genus 

 in his ' Lethsea Bruntrutana,' Zurich, 1864, p. 406. 



G-enus Thamnoseeis, Mallon, LetJicea Bruntrutana, 

 p. 406 (1864). 



Colony in rounded masses or in thin laminae. Epitheca thin 

 and complete. Columella papillary. Septa confluent, thick, 

 covered on their free edge and flanks with very projecting granules 

 which are close together, and constitute more or less numerous 

 synapticula. 



In a description of a species, Thamnoseris Froteana, Etallon, 

 op. cit. p. 406, pi. Ivii. fig. 10, it is stated that the corallum is 

 conical and turbinate, with growth-rings on the inferior plateau, 

 and sometimes even on the circumference of the corallum. Upper 

 surface subplane, or a little convex and irregular. Calicos sub- 

 equal, usually polygonal, with a well-marked centre. Septa 

 unequal according to the orders, of slightly difterent thickness ; 



