15 



PLATE VII. 



Geodia Zetlandioa, Johnston. 



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



Fig. 1. — Sectional view of the type-specimen 

 (Gydonium Mulleri, Fleming) exhibiting tlie radiated 

 strncture 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 hnear. 



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

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



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 attenuato-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 favoiu"ed 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 Pi'o- 

 fessor Fleming, of Edinburgh, to whom I am much 

 indebted for the opportunity of figuring a specimen 

 resrardingf which there has been so much discussion. 

 No other specimens of this interestmg species than 

 the two figured have yet been found in any collection 

 of British sponges. 



