X INTRODUCTION. 



Of the two species of stelletta, 0. Schmidt, S. 

 pumex, a very small fragment, is apparently a Tethea, 

 from the radiating structure of the skeleton, and the 

 numerous porrecto-ternate external defensive spicula 

 at the dermal surface. 



S. discopJiora. Is a pachymatisma with all the 

 characteristic irregularity of the skeletons of that 

 genus. 



The two species of clathria Schmidt are both 

 members of the same genus. 



C. oroides, is a very distinct ophlitaspongia, appa- 

 rently of a slender cylindrical form, with short stout 

 smooth acuate internal defensive spicula. 



C. coralloides is a densely compacted ophlitaspongia 

 with internal defensive spicula of verticillately spined 

 acuate form, very numerous. 



The two Suberites Nardo. 



S. massa is a Hyrneniacidon with spinulate spicula, 

 very closely resembling in structure our British 

 species, H. suberea. 



8. domunculus, is a Hymeniacidon with small 

 spinulate spicula. In general structure it bears a 

 close resemblance to our British species, H. Carnosa. 



Of the two species of Axinella, Schmidt. 



A. verrucosa, is a Halichondria with large acuate 

 spicula ; the skeleton structure is much confused. 



A. potypodoides is a well-developed Isodictya, the 

 primary lines of the skeleton bi-, or trispiculous ; 

 secondary lines rarely more than unispiculous, spicula 

 acerate. 



Of the Adriatic sponges, of which I received only one 

 specimen of each genus- 



Spongelia pallescens, Nardo, is a true spougia. Its 

 fibrous structure and its mode of arrangement is pre- 

 cisely the same as that of the best Turkey sponge of 

 commerce. Its membranous and sarcodous structures 



