22 DR- J- s - BOWERBANK ON THE SPONGIADiE. [Jan. 7, 



Spongiadte,' is very much more largely developed than the subject of 

 our present description ; but several small specimens of C. penicillus 

 that I subsequently obtained are as nearly as possible of the same 

 size and external appearance as those of C. Tyleri. 



DESCRIPTION OF THE PLATES. 

 Plate I. 

 Geoclia Flemingii, Bowerbank. 

 Fig. 1 represents the type specimen based on a mass of Nullipora and sand, 



natural size, exhibiting a portion of the irregular groups of oscula. 

 Fig. 2. A view of the reverse of fig. 1, exhibiting a section of the sponge and its 



hollow interior. 

 Fig. 3. A fully developed attenuato-expando-ternate bifurcated connecting spi- 



culum, magnified 80 linear. 

 Fig. 4. One of the recurvo-ternate spicula, magnified 80 linear. The greater 



number of these spicula have their sbafts very much longer than the 



one represented. 

 Fig. 5. A fusiformi-cylindrical skeleton-spiculum, magnified 80 linear. 

 Fig. G. One of the large cylindro-stellate retentive spicula with numerous short 



radii, magnified 530 linear. 

 Fig. 7. A simple cylindro-stellate retentive spieulum, magnified 530 linear. 

 Fig. 8. One of the small cylindro-stellate retentive spicula, magnified 530 



linear. 



Gcodia deprcssa, Bowerbank. 

 Fig. 9 represents the type specimen in the Museum of the Royal College of Sur- 

 geons, London : natural size. 

 Fig. 10. Half of one of the large fusiformi-aeerate skeleton-spicula, magnified 



80 linear. 

 Fig. 11. One of the large attenuato-patenti-ternate connecting spicula with large 



and long shafts, magnified 80 linear. 

 Fig. 12. A recurvo-ternate connecting spieulum with long and slender shafts, 



magnified 80 linear. 

 Fig. 13. An attenuato-stellate retentive spieulum from the interstitial membranes, 



magnified 530 linear. 

 Fig. 14. One of the small and very numerous cylindro-sphero-stellate retentive 



spicula from tho interstitial membranes, magnified 530 linear. 

 Fig. 15. An adult ovarium, magnified 230 linear. 



Gcodia c/iblcrosa, Bowerbank. 



Fig. 16 represents the specimen in the possession of Dr. Andrew Fleming, son 

 of the late eminent naturalist Professor Fleming of Edinburgh : natu- 

 ral size. 



Fig. 17. One of the attenuato-patenti-ternate connecting spicula, magnified 80 

 linear. 



Fig. 18. A fusiformi-aeerate skeleton-spiculum, magnified 80 linear. 



Fig. 19. One of the slender acuate skeleton-spicula, magnified 80 linear. 



Fig. 20. A small fusiformi-aeerate tension-spiculum from the interstitial mem- 

 branes, magnified 80 linear. 



Fig. 21. An attenuato-stellate retentive spieulum from the interstitial mem- 

 branes, magnified 530 linear. 



Fig. 22. One of the minute cylindro-stellate retentive spicula, magnified 530 

 linear. 



Plate II. 

 Gcodia ferarmatus, Bowerbank. 



Fig. 1 represents the type specimen, natural size. 



Fig. 2. One of the large fusiformi-aeerate skeleton-spicula, magnified 80 linear. 



