SELENARIID^E. 67 



.2. C. CANARIENSIS, Busk. PL XIII, fig. 2. 



Polyzoario crateriformi, orbiculari, inargine denticulata ; cellularuni area rhombica ; 

 aperturd subquadrangulari, oblonga, niargine Integra ; vibraculi orificio auriculari, alte 

 canaliculate. Superficie dorsali sulcata, liris in areas quadrangulares poris niajoribus 3 

 ornatas partitis. 



Polyzoarium cup-shaped, orbicular ; area rhombic ; aperture subquadrangular, oblong, 

 margin entire ; lamina finely granular ; vibracular opening auricular, deeply channelled ; 

 posterior surface sulcate, the ridges divided into quadrangular portions, in each of which 

 are 3 6 rather large pores. 



C. CANAKIENSIS, Busk, Q. J. M. Sc., vii, p. 66, Zooph., pi. xxiii, figs. !i 9. 



Habitat. C. Crag, Sutton, Ramsholt, S. W. [Recent] Madeira and Canaries, 

 Johnson, M' Andrew. 



3. C. POROSA (. sp.} PL XIII, fig. 5. 



Polyzoario parvo, depresso, orbiculari, lapidis vel conchas particulam hand raro apice 

 includente ; cellularuni area subrhomboidali ? apertura margine denticulata ? vibraculi 

 orificio - ? Superficie dorsali delicatule sulcata, liris planatis, porosis, subrugosis. 



Polyzoarium less than \" in diameter, flattened, orbicular, often including a fragment 

 of stone or shell at the summit; area subrhomboidal ? aperture with a toothed margin r 



vibracular orifice ? posterior surface finely sulcate ; ridges flattened, minutely porous, 



subrugose. 



Habitat. Cm. Crag, 8. W. 



The distinguishing characteristics in the more worn condition of C. denticulata, cana- 

 riensis, and porosa, have already been adverted to, and it is unnecessary here to remark 

 further upon them. C. porosa seems to be one of the smallest of the Selenariidse, for 

 specimens bearing all the marks of considerable age do not exceed, or rarely equal \" in 

 diameter. A very common circumstance in, and, so far as I am aware, peculiar to this 

 species, is the existence at the summit of the disc, that is to say, on the convex side, of an 

 angular particle of stone or shell, around and upon which the cells are formed, spreading 

 over it like those of a Lepralia, and in some cases, entirely enclosing the foreign body, of 

 which no part, it is to be remarked, is visible on the iinder or concave side, which is the 

 usual site for similar particles in many other Luuulites. 



