333 



former from the China Sea. In his description of A. circinata Busk mentions a 

 supposed bundle of muscles, which is attached to the accessory part of the 

 operculum, but in reality it is only a connected part of the compensation-sac, 

 which by foldings has assumed a longitudinally striated appearance. 



Etnballotheca n. g. 

 Scbizoporella p. p., Lepralia p. p. 



No spines. The zooecia with numerous scattered pores. The aperture has a 

 weakly developed vestibular arch and its poster is usually convex or provided 

 with a low sinus, more rarely with a broad, tooth-like projection. The operculum, 

 the muscles of which are attached near the lateral margins, is chitinized to a 

 very varying extent and not always distinctly marked off from the compensation- 

 sac. Well-developed hinge-teeth. Small avicularia with rounded mandible at the 

 tip may occur in various positions, but are most frequently lateral with the 

 mandible directed obliquely proximally or inwards. The hyperstomial ooeciam 

 consists of a membranous ectoooecium and a calcified endoooecium with or without 

 pores, but between the two layers there is inserted a more strongly calcified 

 cryptocyst layer, provided with pores, which is often formed by three or four 

 zooecia in common; in such a case it consists of just as many pieces separated 

 by distinct sutures. The uniporous rosette-plates are fairly numerous. 



To this genus belong E. (Schizoporella) furcata Busk, E. (Lepralia) quadrata 

 Mac Gill, and E. (Schiz.) subimmersa Mac Gill. 



The most striking character of this genus, which for the rest comes nearest 

 to Schizoporella, is the presence of a cryptocyst layer between the two layers of 

 the ooecium, which may sometimes be formed by the distal zooecium alone, 

 sometimes also by two or several adjacent zooecia, and in the last case this layer 

 consists of three or several pieces meeting in distinct sutures. The reason for 

 this difference is simply, that the basal wall of the ooecium only extends in the 

 first case over a part of the distal zooecium, whilst in the last it also extends 

 in over an adjacent part of the neighbouring zooecia, each of which then takes 

 part in the formation of its frontal wall. The earliest sign of such an ooecium 

 is in E. furcata shown in zooecia with frontal wall completely calcified, and it 

 appears here as a hollowed-out area the boundaries of which are formed, some- 

 times merely by a low, arch-shaped cryptocyst ridge, sometimes also by the 

 lateral margins of the zooecium. The area mentioned like the rest of the surface 

 of the zooecium is covered by a membrane, and the part of this which covers 

 over the area is destined to become the basal wall of. the ooecium, whilst the 

 low ridge is the first sign of the cryptocyst layer which grows into the ooecial 



