1863.] DR. J. S. BOWERBANK ON THE SPONGILLID^. 455 



An average-sized spiculum of the skeleton measured, length 

 y^ inch, greatest diameter y^ij-j inch. 



Spongilla reticulata, Bowerbank. 



Sponge massive, sessile ; surface spiniferous, interspaces closed by 

 a coarse reticulation of spicula. Oscula, pores, and dermal mem- 

 brane obsolete. Skeleton-spicula subfusiformi-cylindrical, short, 

 and stout. Ovaria spiculous, encased in an oval, irregular, and 

 coarse reticulate envelope of spicula ; surface of envelope even. 

 Spicula of envelope cylindrical, slightly curved, entirely spined, 

 short, and stout. Ovaria oviform, thin ; surface smooth ; foramen 

 tubular: spicula boletiform ; large internal extremity, externally 

 convex, internally concave, margin entire ; small external extre- 

 mity, clavate, sometimes stellate ; shaft more or less attenuating 

 from each end towards the middle, furnished irregularly with a few 

 conical spines. 



Colour, dry state, dark green, with a brown tint. 



Hab. River Amazon, on pendent branches of trees. 



Examined in the dried state. 



I received nine fine specimens of this interesting species from Mr. 

 Bates. The label accompanying them states that they were from 

 "Dark Ygapos in virgin forest, margins of Amazon, Villa Nova 

 (when the waters have receded, found chnging to the trees), Nov. 

 20, 1854." The largest specimen surrounds a curved branch of a 

 quarter of an inch thick. The Sponge is fusiform, 9 inches in length, 

 and 2 inches at the greatest diameter in thickness ; the surface is 

 irregularly tubercular. The other specimens vary considerably in 

 form, following the direction of the branches, which they surround 

 completely, although frequently not more than the eighth of an inch 

 in thickness ; and of the very young specimens, four of which occur 

 on different branches of the same stem, one, although not more than 

 half an inch long, has already succeeded in entirely embracing the 

 stem. 



The superficial interspaces are closed by a coarse rigid network of 

 spicula. Through this the terminations of the primary fil)res of the 

 skeleton are projected a line or more in length, forming stout conical 

 spines all over the surface. The internal interspaces are also more 

 or less filled with a similar network to that which closes the super- 

 ficial ones. 



The spicula of the skeleton are short, stout, and cylindrical, with 

 a slight inclination to be fusiform, especially when large and fully 

 developed ; the terminations are hemispherical. 



The ovaria are abundant in all parts of thg Sponge. The envelope 

 is composed of a coarse, irregular network of spicula, the interstices 

 being filled in by membranes thickly coated with sarcode. The spi- 

 cula are cylindrical, with hemispherical terminations, and they are 

 furnished in all parts with short conical spines. The envelope is 

 sometimes observed attached, by one side, to a large fibre ; at other 

 times it is supported in an interspace by two or three short pedicels 

 of spicula. The ovarium fills the interior of the envelope ; it is ovi-- 



