some Irish Sponges. 235 



The species was dredged at three stations off tlie south- 

 west coast of Ireland, at depths varying from 250 to 

 560 fathoms. 



Esperiopsis incognita, sp. n. 



The sponge is growing in a very thin encrustation on 

 coral. 



The skeleton consists of short fibres made up of multi- 

 serialjy arranged styli, which run obliquely through the 

 sponge from base to surface. In addition to these fibres there 

 are thick, well-defined, branching fibres running more or less 

 parallel to the surface of the sponge. 



Spicules. — (1) 8tyli, straight and slender, 0*I-0'45 mm. 

 in length by 0-006-0-008 mm. (2) Isochelse palmatse of 

 two forms — (a) straight isochelae with rather long, narrow 

 alai leaving only a short part of the sliaft free. Length 

 0"035-007 mm. ; {h) very small, slender isochelce, with 

 slightly curved shaft, 0*013 mm. in length. (3) Sigmata of 

 iwo forms — (a) sigmata lying in one plane and varying a 

 good deal in size. The longer axis is from 0*l-0*32 mm. in 

 length. The maximum thickness of the spicule is about 

 0"0I3 mm, ; (Z») slender, contort sigmata with a longer axis 

 of 0-0I-0'075 mm. 



This sponge is identical with the specimen referred to by 

 Carter as " an unknown sponge/' and partly described and 

 figured by him under that name {Journ. Roy. Micr. Soc. ii. 

 1879). 



The sponge was dredged oflp the west coast of Ireland in 

 388 fathoms. 



Esperiopsis macrosigma, sp. n. 



The sponge is growing in a very thin encrustation on 

 coral. 



The skeleton consists of bundles of spicules, or of short 

 fibres containing multiserially arranged spicules. In places 

 longer, rather ill-defined fibres run more or less parallel to 

 the surface. Tiiere are also single spicules or groups of two 

 or three spicules scattered through the sponge. 



Spicules. — (1) iStyli slender, straight, tapering to a rather 

 short point. Length 0-37-0-42 mm. by 0006-0-008 mm. 

 (2) Isochelse palmatse of three forms — (a) the largest are 

 0"11-0*125 mm. in length, the shaft is straight and is about 

 O'OOG mm. in thickness. The tooth measures 024 mm. 

 across ; {b) isochelae with ratiier long narrow alse leaving 

 only a short part of the shaft free. Length 06 mm. ; 



