268 NATURAL HISTOEY OF 



Western Coast. It exhibits a variety of modifications 

 of structure, sometimes having perfectly oval and plain 

 cells, and at others having the cells rhomboidal and 

 much punctured. It has the semicircular orifice and 

 sinus characteristic of this and the preceding genus, 

 and below the orifice on a prominent boss-like vibracular 

 cell is a long vibraculum. Eound the orifice of each 

 zooecium is usually a broad collar-like expansion. This 

 species was first dredged off the Coast of Sana Island, 

 near Cantire, in Argyleshire, a coast which Dr. Lands- 

 borough describes as being rich in algae and zoophytes. 



Genus III. Schizotheca, JSinch. {(T')(i^a), I divide, 

 and dn'^icri, a receptacle.) 



Zooecia with a suborbicular primary orifice, the lower 

 margin sinuated ; the secondary orifice raised, tubular, 

 notched in front. Ocecium terminal, with a fissure in 

 the front wall. Zoarium (in British species) adnate. — 

 T. H. 



The sinus in the lower margin of the orifice, which 

 is a characteristic of the present family, is often con- 

 cealed in this genus by a secondary opening which is 

 tubular and armed with spines. 



The generic name is derived from the fissured ap- 

 pearance of the ooecia. 



1. S. FissA, Buslc. Plate XXI. fig. 3. 



Lepralia fissa {Busk, McA.). 



Hab. : Cornwall, Devon [T. H.), Guernsey (Aid.). 



The colonies are silvery-white in colour. The zooecia 

 are ovately rhomboidal, regularly disposed. The orifice 

 of each cell is tubular, with a distinct sinus in front, 

 and is armed with six long spines. The avicularia 



