196 PROCEEDINGS OF THE ACADEMY OF [l-SST. 



iiig skeleton spicules, excepting that immediately under and around 

 each gemmule it is seen tobe})uttressed and supported by scores ofspi* v 

 ules of a skeleton type, resting against it at many angles, and at- 

 taching it to the supporting surfece, as Mr. Carter has said. 

 These, by the way, are obscurely microspined. The aperture of thtr 

 slightly elliptical, or pro-spha^roidal gemmule, is always found at oui- 

 of its poles, and is prolonged into a tubule of moderate length, pn.- 

 voking the comparison to a tortoise with its head i)rotruded. Tht^ 

 layer of gemmule-spicules is "dense" because they are not crossed 

 but lie nearly parallel with each other as if stroked with a brush, 

 and in a nearly transverse direction, corresponding witli the sliorter 

 axis of the ellipse. 



The normal character of the living sponge remains, as Carter left 

 it, an unsatisfied problem; but the aV)sence of surrounding spicules. 

 suggests to me the possibility that the minute body of Sponyilla nav- 

 icella is simply a firmer sarcode unsupported by a skeleton frame 

 work. 

 (9) Spongilla bombayensis, Carter. .Ann. etc. 1SS2, }). .".(i',!. 



"General form of sponge unknown. Statoblast sessile, globular, 

 more or less grouped and firmly attached to the stems of the her- 

 baceous plant upon which it had grown ; variable in size under rh 

 of an inch diameter, composed of a spiculiferous capsule, a chitinous. 

 coat, wdiich is also spiculiferous, and the usual germinal contents, 

 but no distinct cellular coat. Spicules of the statoblast slightly 

 curved, thick, cylindrical, more or less obtuse at the ends ; about 

 9 by 2-6000 ths. of an inch in greatest dimensions ; and another 

 comparatively thin, fusiform, and more or less pointed at the end.s, 

 about 10 by 1-6000 ths. inches in greatest dimensions; both thickly 

 spined, and varying in stoutness invei'sely with their proximity to tht- 

 surface; arranged horizontally, so that the ends do not project beyond 

 the level of the statoblast, where they more or less cross each other 

 and are held together by granules (the microcell structure?); aj*- 

 pearing also in the chitinous coat when they do not cross each other- 

 but form a single layer, in which the spicules lie more or less paral- 

 lel to each other in various directions, so as to present a dama.s- 

 cened appearance. Skeleton -spicules of one form only, viz.-aceratc. 

 curved, fusiform, gradually sharp-pointed, smooth or microspined, 

 about 22 by 1-1800 th. inch in their greatest dimensions. Aperture, 

 of statoblast sunken, single or in plurality, lined by a tubular pro- 

 jection of the chitinous coat." Carter. 



Loc. Island of Bombay. 



