280 SIDNEY F. HARMEE. 



the proximal border of the opercuhim. The divavicator 

 muscles are seen at div. ; occl. indicates the position of the 

 orio-in of one of the occlusor muscles, while a pair of parieto- 

 vaginal muscles are seen at p. v. m. Arising from the sides 

 of the zocecinm are a series of delicate parietal muscles (p. m.). 

 There is a tendency for these to be arranged in a grouped 

 manner. They can be traced along the basal surface of the 

 compensation-saCj into Avhich each is inserted. 



A polypide and a conipeusation-sac occur in both forms of 

 zooecia. Reproductive organs are, unfortunately, absent, so 

 that it is not possible to ascertain whether the dimorphism 

 has any relation to reproduction. 



The compensation-sac develops in what I shall term the 

 Lepralioid manner ; that is to say, as an invagination formed 

 at the base of the operculum after the calcification of the 

 front wall has been completed. Some of the details of this 

 process are described in the account of the next species. 



Euthyroid es, n. gen. — I suggest this term forCarbasea 

 episcopalis, Busk,^ a form placed by Hincks ^ in the genus 

 Euthyris. The diagnosis of the genus may bo given as 

 follows : 



Zoarium of Flustra-like habit, bordered along each edge 

 by a tube, interrupted at intervals, which represents a part of 

 the body-cavity not divided into zooecia, but without other 

 spaces beneath the epitheca. Frontal wall more or less 

 calcareous, covering a well-developed compensation-sac. Com- 

 munication-pores large, typically four on each side. Ovicells 

 large, external, with a wall composed of two calcareous layers. 

 The genus differs from Euthyris in the absence of spaces 

 beneath the epitheca and in the presence of large external 

 ovicells, and of a very different type of communication-pore. 



The zooecia of E. episcopalis (PI. 15, figs. 13 — 17) are 

 extremely elongated. Their vertical and basal walls are 

 calcified, but there is so little calcareous matter in the frontal 



' Busk (1S52), p. 52; MacGillivray, 'Prod. Zool. Vict.,' 1, Dec. v, ISSO, 

 p. 28. 

 » 'Ann. Mag. Nat., liisf.' (5), x, p. IGI. 



