some Irish Sponges. 241 



Spicules. — (1) Acanthostyli. The long acanthostyli are 

 very slightly curved and taper to a rather long point. The 

 head is well marked and is rounded ; it is thickly covered 

 with short, stout, blunt spines. A few small spines are 

 scattered along the shaft. These spicules measure about 

 0'5-0'8 mm. in length by 0'013 mm. above the head. The 

 short acanthostyli are straight and taper to a long fine point. 

 The head is fairly well marked and is covered with rather 

 strong blunt spines. The shaft is thickly set with small 

 recurved spines. The length varies from 0'12-0*17 mm. by 

 0*008 mm. (2) The dermal spicules are slender subtylostyli, 

 very minutely spined on the head. The shaft is often rather 

 curved. The length is about O'S-O'-l mm. by 0'003 mm. 

 (3) Isochelse palmatas, very minute, measuring only O'OOS 

 mm. in length. 



The species was dredged off the south-west coast of Ireland 

 in 250-542 fathoms. 



Axinella pyramidata, sp. n. 



The sponge, which is cut off from its support, is 15 mm. in 

 height and 17 mm. in diameter at its summit. In shape it is 

 somewhat like a three-sided pyramid standing on its apex, 

 except that the sides are deeply cut vertically into a series 

 of flattened lobes. The upper surface is flat, but here and 

 there it rises into small knob-like elevations. 



The skeleton consists of closely-set plumose columns of 

 spicules which run upwards through the sponge, and then 

 bend out towards the surface, where they end in brushes of 

 styli which project for part of their length beyond the dermis. 

 A considerable amount of spongin is present, cementing the 

 spicules together. 



Spicules. — (1) Styli varying from about 0"23 mm. to 1 mm. 

 in length by 0*01-0"016 mm. In the shorter styli the 

 shaft is rather sharply bent at a little distance above the 

 head. The longer styli are usually slightly curved. There 

 is sometimes a slight swelling on the shaft a little distance 

 above the head. (2) Oxea about 0'3-0'6 mm. in length by 

 001-0"013 mm. They are sharply and irregularly bent, and 

 taper at either end to a rather short point. Many of the 

 oxea have a slight swelling about the middle of the spicule. 



The only specimen in the collection was dredged off the 

 Kerry coast in 37 fathoms. 



