I2S The hish Nahiralist. 



Habitat : River Barrow (Mr. T. Greene) ; Raheny ponds, Co. Dublin 

 (Dr. R. F. Scharff); probably common throughout the country —Great 

 Britain, France, Germany, Bohemia, Galicia, Russia, Italy, and throughout 

 the Eastern and Middle United States generally. 



Ephydatia Miillerl, Lieberklihn. (Plate 4, fig. 4). Encrusting, 

 with smooth surface, sometimes with short branches. Green, yellow, 

 yellowish brown, white. Skeleton-spicules straight or slightly bent, 

 suddenly pointed, smooth or rough, or smooth and rough spicules mixed. 

 Shaft of the amphidiscs short, rays of the rotules smooth or indented. 



Habitat : McHugo Island, Lough Rea, Loughrea, Galway (Mr. S. R. 

 Christophers), about 150 feet above sea level. —England (River Exe, 

 Devonshire), France, Germany, Bohemia, Russia. Probably also in the 

 United States, but Potts gives no locality, as he fuses this species with 

 E. fliiviafilis. 



Our Irish material consists of a few small circular patches, each about 

 10 mm. in diameter and i or 2 mm. in thickness, of yellowish grey colour, 

 when alive. Its skeleton-spicules appear shoit and stout, suddenly 

 pointed, both the smooth and rough variety of spicules are present, 

 measuring about 0*25 by 0*02 mm. 



Ephydatia crateriformis, Potts. (Plate 4, fig. 5). Thin, encrust- 

 ing. Colour of gemmules white or yellowish. Skeleton-spicules slender, 

 gradually pointed, slightly spined. Tubule of the gemmule standing at 

 the centre of a crater- like depression. 



Habitat : (doubtful) : Park Lough, Hungry Hill, 300 feet above sea- 

 level (R. I. A. Flora and Fauna Committee), — Occurs in various localities 

 in North America (for details see Potts, 7, p. 229). 



We have only two specimens from the Irish locality. They are small, 

 uneven, somewhat lobular masses, about 10 mm. in diameter and 4 mm. 

 in height. The skeleton-spicules are slender, o"2i to 0'33 mm. by 0007 

 mm., straight or only very little bent, slightly spined, often irregularly 

 inflated, and such inflated portions of the spicules are always free from 

 spines. The corresponding spicules as described and figured by Potts 

 measure 0*27 by o-oi mm., and show no such inflations. The Irish 

 specimens contained no gemmules, but scattered throughout the tissue 

 of the sponge there are exceedingly slender spicules with swollen ends, 

 with most minute spines which may be immature amphidiscs, measuring 

 0-036 to 0'045 mm. by 0*0025 i^m. Potts (7, p. 229) describes similar 

 spicules in his American material, measuring about 0*062 by o'oo3 mm. 



Hetcromeyenfa, Potts. 



Skeleton-spicules as in Ephydatia. The gemmules surrounded by 

 intermingled amphidiscs of two tj'pes, whose shafts are of unequal length* 

 The proximal rotules of all rest upon the chitinous coat ; the outer 

 extremities of the less numerous rotules project beyond the others. 



Hetcromeycnia Rydcrl, Potts. Light green, massive. Skeleton 

 spicules fusitorm, gradually pointed, entirely spined, except at their 

 ends. Rotules of long amphidiscs with three to six short recurved 

 hooks. Rotules of short amphidiscs with straight rays. 



