12 Proceedings of the Royal Irish Academy. 



exactly with those of the type, except that the large acanthostyli are rather 

 shorter, their maximum length being 0*31 mm. as against 041 mm. of the first 

 found specimen. 



This is the first time that a sponge belonging to the genus Hymenancora 

 has been found within the Irish area. 



Microciona laevis Bowerbank. Plate I. tig. ?.. 



ll.D.S. Survey. Station 124, 50 miles W. of Bolus Head, 220 fathoms. 



The sponge is growing in two small patches on pieces of coral (Zophohelia 

 prolif' ■'/•(» . Its surface is very hispid. .As far as can be seen from the scanty 

 material available for examination, the dermal spicules are collected together 

 in vertical brushes, their ends projecting above the surface of the sponge. 

 The skeletal fibres an- very short and plumose, the smaller styli being placed 

 towards the exterior of the fibre. The long styli project far above the surface 

 of the sponge. There is a considerable quantity of spongin round the bases 

 of the styli. 



Spicules — (1). The skeletal styli vary wry much in size. The largest 

 reach a length of about 14mni„ and are 0*024 mm. in diameter above the 

 head. The shaf _ urved and tapers Inwards one cud to a rather 



short point, and at the other end the rounded head is slightly constricted off 

 from the shaft, and i.~ smooth or is set with a few minute Bpines. The smallest 

 ,-tyli are about 0*14 mm. iu length, with a diameter of 0007 mm. above the 



1. They are of the same shape as the la !i. but are furnished with 



minute spines al a -haft, as well as having the head well spined. These 

 two extremes are united by styli of intermediate sizes and degrees of 

 spination. 



- The dermal styli have a vei sometimes rather crooked, 



shaft, and the head is niicrospined. Their length varies from about 0*5 to 

 0*78 mm., and the maximum diameter is 0*0(h; mm, 



(3) The toxa are scattered in great abundance throughout the sponge. 

 Their shape is very constant, but they vary greatly in size, from extremely 

 minute to about 0*16 mm. in length, with a thick 0004mm. The 



curve in the middle of the spicule is even, and uot very abrupt, and the ends 

 are slightly re-curved, and sharply poin 



This species has been taken only once previously, namely, off the 

 Shetland:, 1 >. 



Plocamia microcionides 1 1 



ELD.S. Survey. Station L24, 50 milec W. ol Bolus Head 220 fathoms. 

 The specimen i~ spreading iies of a coral (Lophofo 



prol wily picked out from among the numerous encrusting 



