hnoion /Species o/" Spongilla. 91 



* Margin of disks even. 

 1. Meyenia erinaceus. 

 Spongilla erinaceiis, Ehr. apud Lieberkiihn, No. 15, p. 509. 



Of this species Lieberkiihn says, " Zeichnet sich durch 

 Nadehi aus, welche auf ihver Oberflache mit kleinen Stacheln 

 versehen &ind ;" but the spinous character of this spicule here 

 does not appear to be such a valuable character, in a specific 

 point of view, as the disks of the birotulate spicule of the 

 statoblast, which Lieberkiihn describes in the following page 

 to be without denticulation, and represents as umbonate with 

 even circular margin and short sliaft (No. 15, Taf. xv. 

 fig. 31). 



Log. River Spree, Berlin. 



Ohs. This sponge appears otherwise, ^. e. in structure and 

 spiculation, to be like Meyemia Jluviatilis. I do not know 

 where Ehrenberg has described it. 



2. Meyenia Leidii. 

 Spongilla Leidii, Bk., No. 20, p. 7, pi. xxxviii. fig. 2. 



Thin, sessile, coating. Surface tuberculated, minutely 

 hispid. Structure friable, crumbling. Skeleton-spicule curved, 

 fusiform, abruptly sharp-pointed, sparsely spiniferous, becom- 

 ing much smaller and more spined round the statoblasts. 

 Statoblast globular, aperture infundibular ; crust composed oi 

 granular substance charged with birotulate spicules possessing 

 very short shafts and evenly margined smooth umbonate disks, 

 both of which have the margins more or less everted or turned 

 outwards (that is, from the statoblast), arranged perpendi- 

 cularly on the chitinous coat. 



Loc. Schuylkill river, Pennsylvania. 



3. Meyenia gr eg aria. 

 Spongilla gregaria, Bk., No. 20, p. 14, pi. xxxviii. fig. 7. 



Sponge unknown. Skeleton-spicule cylindrical, stout and 

 rather short. Form of statoblast not mentioned ; crust charged 

 with birotulate spicules composed of a short thick shaft termi- 

 nated at each end by a simple umbonate disk with even circu- 

 lar margin, arranged perpendicularly to the chitinous coat. 

 Spicules in the immediate neighbourhood of the statoblast 

 cylindrical, slightly curved, and abundantly spiniferous, vary- 

 ing considerably in size. 



Loc. River Amazons. 



Ohs. Having no specimen of this species to refer to, I got 

 Mr. Stuart Ridley, F.L.S., of the British Museum, to examine 

 the mounted specimens of Spongilla gregaria and S. reticulata^ 



