On Mammals from the E. Indian Archipelago. 383 



cytes. Astrosclera is, in my opinion, a purely siliceous 

 sponge, and does not secrete aragonite. 



Summary. — Astrosclera willeyana, Lister, is an Ectyonine 

 sponge with a supplementary skeleton formed of foreign 

 particles of aragonite, the latter being at first discrete, and 

 later welded into concrete walls and blocks. 



EXPLANATION OF PLATE XI. 



Astrosclera wilUyana, Lister. 



Figs. 1-3. Specimens, nearly nat. size. 



Fig. 4. Surface of specimen 3, X 10. 



Fig. 5. Longitudinal vertical section of soft tissues of a decalcified 

 specimen, X 7. 



Fiy. 6. The same, x 16, showing acanthostyles in the walls of the 

 choanosome and below the ectosome. This figure should 

 have shown embryos. 



Fig. 7. The same, X 65. 



Fig. 8. Acanthostyle from Christmas Island specimen, x 700. 



Fig. 9. Ditto from Lifu specimen, X 700. 



Fig. 10. Aragonite spherules, nearly but not wholly decalcified, with 

 remains of radiating lines of particles deeply stained, the 

 whole apparently imbedded in cell-like masses of protoplasm 

 (? remnants of ground substance) ; no nuclei visible. X 1000. 



LVI. — New Mammals from the E. Indian Archipelago. 

 By Oldfield Thomas. 



(Published by permission of the Trustees of the British Museum.) 



Pteropus Hops, sp. n. 



Very similar externally to Pt. temminckii, and agreeing 

 with it in size, quality and distribution of fur, and general 

 colour, but differing in the following details : — Face (in- 

 cluding cheeks and chin) uniformly pale brown, without any 

 tendency to the formation of eye-rings ; in temminckii the 

 face generally is whitish, the cheeks especially, while there 

 are perceptible brown eye-rings carried forward anteriorly 

 nearly to the nose, and contrasting with the narrow median 

 buffy-whitish frontal line between them. Under surface, 

 from sternum backwards, dark broccoli-brown, the hairs of 

 this part being in temminckii broadly tipped with pale buffy. 



Skull with the orbits markedly smaller than in temminckii. 



Forearm of type 102 mm. 



Hab. Buru Island. 



Type. Subadult female. Original number 892. Collected 

 August, 1909, by Mr. W. Stalker. 



