The Ff'esh-water Sp07tges of Ireland. 127 



I now propose to give a short description of the Spongillidae 

 so far found in Ireland, with the addition of Sp07igillafragilis. 

 By doing so the following list will at the same time include 

 all British Spongillidse and thus be useful to British collectors 

 too. Besides, S. fragilis is sure to be found some day in 

 Ireland, being, next to Eusp07igilla lac2istris, the most common 

 fresh-water Sponge of Europe and N. America. 



Euspongrilla, Vejdovsky. 



Skeleton-spicules oxeote, generally smooth, accompanied by short, 

 either straight or curved, smooth or rough flesh-spicules. Gemmules 

 always single, and covered with oxeote and almost always spined 

 spicules. 



Euspongrilla lacustris, Autt. [PI. 4, fig. 1.] Forming finger-like 

 branches arising from an encrusting base. Colour grass-green, yellowish, 

 brown. Skeleton-spicules, smooth oxea, straight or slightly curved, 

 gradually pointed. Flesh-spicules slightly curved, minutely spined. 

 Gemmules globular, the covering spicules strongly spined, and more or 

 less curved, tangentially or radially arranged. 



Habitat : Camlough River, Co. Armagh (R. LI. Praeger) ; dry drain, 

 Killakeen, Co. Cavan (R.I. A. Flora and Fauna Committee) ; probably in 

 numerous other localities in Ireland. Common throughout Great 

 Britain, Europe generally, Siberia, and, according to Potts (7, p. 200), 

 the most widely distributed fresh-water sponge of the United States. 



[Spong-illa, Wierzejski. 



With the characters of Euspongilla, but gemmules in groups of two to 

 thirty enclosed by a common covering. (Often considered as subgenus 

 of Euspongilla). 



Spong-illa fragrilis, Leidy. (Plate 4, fig. 2). Encrusting, never 

 branching, surface smooth. Colour from light grey to brown, rarely 

 green. Skeleton-spicules straight or very slightly bent, rather abruptly 

 pointed, smooth. With little spongin, therefore easily broken. Covering 

 spicules of gemmules generally larger than those of Euspongilla laciisiris, 

 straight or curved, with numerous minute spines. No flesh-spicules. 



Habitat : Not yet found in Ireland. Occurs in England (River Wye, 

 near Hereford), France, Germany, Bohemia, Galicia, Russia, and next 

 to Euspongilla laaistris, the most widely distributed fresh-water sponge 

 of North America: (Potts, 7, p. 200).] 



Ephydatia, Lamouroux. 



With either smooth or rough skeleton-spicules, or with both. The 

 gemmules surrounded by radially-arranged amphidiscs of a single type 

 only. The rotules with star-shaped margins. 



Ephydatia f luviatllis, Autt. (Plate 4, fig. 3). Encrusting, massive. 

 Emerald green to light yellow-brown. Skeleton-spicules smooth, 

 fusiform, slightly bent, gradually pointed. The shafts of the amphidiscs 

 smooth or spined, twice as long as the diameter of the rotules ; rays of 

 the rotules deeply cut. 



