44 Mr. W. J. Sollas on a new 



bearing on its inner surface the seminal organ, which is also 

 bulb-shaped and tapers above into a long spine-like corneous 

 process ; relative length of legs 2,4, 1,3; cephalothorax and 

 abdomen together, of $ 7 millims., of ? 8 millims. 



I have to thank the Rev. O. P. Cambridge for referring me 

 to the genus of this species. 



7. Gasteracantha madagascariensis 1 ?, var. 



Gasteracantha madagascariensis, Vinson, Aran, cle la Reunion, Maurice 

 et Madagascar, p. 242, pi. ix. fig. 6 (1863). 



In coloration the example sent agrees far better with G. 

 rnauritia of Walckenaer, the cephalothorax and femora being 

 reddish castaneous, the tibias and tarsi black, the abdomen 

 above (in the spirit-example sent) buff-yellow, with black 

 spines and depressed spots (" sigilla," Cambr.), below black 

 spotted with yellow. The Rev. O. P. Cambridge thinks it 

 more probably a variety of G. madagascariensis ; and if this 

 be so, I see no reason why the latter should not be conspecific 

 with G. mauritia, since the difference of form, so far as I can 

 judge, seems to be very slight between these two spiders. 



As regards the strange modification of pattern which must 

 have taken place if this be in truth a pale variety of G. mada- 

 gascariensis, I may mention that, so far as can be determined 

 from dried specimens, G. flavomaculata seems to show a ten- 

 dency towards a similar modification. 



EXPLANATION OF PLATE I. 



Fig. 1. Pasithea foliifera, Butl. (twice the natural size). 1 a. Profile 



"view of the same, slightly enlarged. 

 Fig. 2. Attits Bewsheri, Butl. (twice the natural size). 2 a. The same, 



in profile. 

 Fig. 3. Attus Johannes, Butl. (twice the natural size). 3 a. The same, in 



profile. 3 b. Male palpus, much enlarged. 

 Fig. 4. Attus anjuanus, Butl. (twice the natural size). 4 a. The same, in 



profile. 

 Fig. 5. Spermophora co?noroetisis, Butl. (twice the natural size). 5 a. The 



same, in profile. 5 b. Male palpus, much enlarged. 



IV. — On Plocamia plena, a new Species of Echinonematous 

 Sponge. By W. J. Sollas, M.A., F.G.S., &c. 



[Plates VI. & VII.] 



Plocamia plena , n. sp. (PL VI.) 



(Examined in the dry state.) 



Sponge fan-shaped (PI. VI. fig. 1) : a horizontal incrusting 

 base (?>), 2V inch thick, smooth and irregular on the under sur- 



