15 



PLATE VII. 



GEODIA ZETLANDICA, Johnston, 



Vol. ii, p. 45, ' Mon. Brit. Spongiadse.' 



Fig. 1. Sectional view of the type-specimen 

 (Gy donium Mulleri, Fleming) exhibiting the radiated 

 structure of the specimen. Natural size. 



Fig. 2. View of the external surface of the same 

 specimen. Natural size. 



Fig. 3. A sectional view of the specimen of the 

 same species of sponge which I received from Mr. J. 

 de C. Sowerby. Natural size. 



Fig. 4. View of the external surface of the same 

 sponge as No. 3. Natural size. 



Fig. 5. One of the fusiformi-acerate skeleton 

 spicula from the type-specimen. X 80 linear. 



Fig. 6. One of the attenuato-patento-ternate, con- 

 necting spicula from the type-specimen. X 80 linear. 



Fig. 7. An attenuato-recurvo-ternate spiculum 

 from the type -specimen. X 80 linear. 



Fig. 8. A porrecto-ternate spiculum from the type- 

 specimen. X 80 linear. 



Fig. 9. A large and a small attenuate- stellate 

 spiculum from the interstitial membranes of the type- 

 specimen. X 250 linear. 



Fig. 10. A fully-developed ovarium from the type- 

 specimen, with the foramen in its centre. X 250 

 linear. 



Through the kind intervention of my friend Dr. 

 McBane, of Edinburgh, I have been favoured with the 

 loan of the highly interesting and valuable type-speci- 

 men of Geodia Zetlandica, Johnston, by Dr. Andrew 

 Fleming, of Seagrove, son of the late eminent Pro- 

 fessor Fleming, of Edinburgh, to whom I am much 

 indebted for the opportunity of figuring a specimen 

 regarding which there has been so much discussion. 

 No other specimens of this interesting species than 

 the two figured have yet been found in any collection 

 of British sponges. 



