262 ANATOMY AND PHYSIOLOGY 



SPICULA OF THE OVARIES AND GEMMULES. 



1ST. SPICULA ELONGATE, DISPOSED AT RIGHT ANGLES TO 

 LINES RADIATING FROM THE CENTRE OF THE GEM- 

 MULE TO ITS SURFACE. 



Fm. 



1 201. ACERATE. X 30 linear. This form occurs abun- 

 I 202. dantly in the envelope of the ovary of Spongilla 

 Carteri, Bowerbank, from the water-tanks of 

 Bombay; and in Sp. Brownii, Bowerbank, from 

 the River Amazon. In both these species the 

 spicula of the ovaries agree in form with those of 

 their respective skeletons, but are not more than 

 half their size. Eig. 201, a spiculum of the enve- 

 lope of the ovary of Spongilla Carteri. Fig. 202, 

 a spiculum of the envelope of the ovary of Spongilla 

 Brownii. Page 58. 



O 



203. SUBARCUATE ACERATE : ENTIRELY SPINED. X 660 



linear. The envelope of the ovary of Spongilla 

 lacustris, Johnston, abounds in this form. The 

 length and mode of spination of these spicula are 

 nearly the same in all of them, but the amount of 

 curvature varies from almost straight to nearly a 

 semicircle, as represented by Fig. 203 ; and in one 

 case the terminations of the spiculum have crossed 

 each other, forming a loop. In some sponges the 

 spicula of the ovaries agree in form with those of 

 the dermal membrane, but this is not the case in 

 the present instance, those of the membrane being 

 slender fusiformi-acerate. Pages 38, 58, 137. 



204. FUSIFORMI-ACERATE : ENTIRELY SPINED, SPINE CYLIN- 

 DRICAL. X 660 linear. These spicula are long, 

 slender, and very slightly curved; they are dis- 

 persed abundantly in the envelope of the ovary 

 of Spongilla Batei, Bowerbank, from the River 

 Amazon. 



