90 Mr. H. J. Carter on the 



bnlar (fig. 3) ; aperture infundibular (fig. 3, (7) ; crust com- 

 posed of pyramidal columns of dodecaliedral or polygonal cells, 

 hexagonal in the section, regularly arranged one above 

 another, in juxtaposition (fig. 3, d and ?), perpendicularly to 

 the outside of the chitinous coat (fig. 3, c), on Avhich, by the 

 intervention of a layer of the statoblast-spicules (fig. 3, e), 

 they rest, surrounded by a layer of minute, fusiform, curved 

 acerates thickly spined, especially over the ends, where the 

 spines are longest and recurved (fig. 3, h), arranged tangen- 

 tially (fig. 3, /') ; the same kind of layer immediately round 

 the chitinous coat, where the spicules appear to be intermixed 

 with the lower cells of the crust, leaving the latter free between 

 the two (fig. 3, e) . 



hoc. Unknown. 



Ohs. Of this species I can state nothing more than that a 

 small fragment appeared in the Bowerbank collection labelled 

 " Spongilla, new species, from the Jardin des Plantes." While 

 it affords another instance of the crust of the statoblast being 

 composed of apparently hexagonal cell-structure like that of 

 Spongilla Carteri, the rigidity and vitreous appearance of 

 the skeletal structure, if not the form of the spicule also, allies 

 it to Spongilla corallioides, Bk., which will be seen hereafter 

 to come from Uruguay. Finally, as this peculiar rigidity of 

 the skeletal structure has in addition only been found in two 

 species of Sjpongilla (viz. S. Batesii and S. reticulata^ Bk.) 

 from the river Amazons, it may be assumed that S. nitens also 

 comes from South America. The presence of a layer of sta- 

 toblast-spicules on the inside as well as on the outside of the 

 crust will be seen by-and-by to occur also in the statoblast of 

 Parmula {^Spongilla) Batesii. 



Metenia*. 



Gen. Char. Skeleton-spicule acerate, curved, fusiform, 

 sharp-pointed, smooth, sometimes more or less spined, or 

 more or less inflated in the centre. Statoblast globular or 

 elliptical ; crust composed of the granular structure mentioned, 

 charged with birotulate spicules, i. e. spicular bodies which 

 consist of a straight shaft terminated at each end by a disk, 

 even or denticulated at the margin (PI. V. fig. 6, A, &c.), 

 arranged perpendicularly around the chitinous coat, so that 

 one disk is applied to the latter, while the other forms part of 

 the surface of the statoblast (fig. 6, e) . 



* " Meyenia,'''' after Meyen, who first pointed out that the statoblast 

 was partly composed of birotulate or amphidiscal spicules (l. c). 



