32 MR. HOLDSWORTH ON A RARE CEYLONESE SPONGE. [Jail. 7, 



Fig. 2 represents the outer or inhalant surface of the sponge, with the remaining 



portion of its short pedicel. 

 For its anatomical structure see Plate VI. fig. 7. 



Plate VI. 



Dysidea conica. 

 Fig. 1 . The type specimen, natural size. 



Isodictya Domicilii. 



Fig. 2 represents the type specimen, natural size. 



Fig. 3. A section, at right angles to the dermal surface, exhibiting the skeleton- 

 reticulations and the interstitial membranes and their spicula, magni- 

 fied 80 linear. 



Fig. 4. One of the very small acuate spicula from tli3 dermal membrane, magni- 

 fied 250 linear. 



Fig. '5. A full-sized skeleton-spiculum, magnified 250 linear. 



Fig. 6. One of the smaller skeleton-spicula from the interstitial membranes, 

 magnified 250 linear. 



Spongionclla Holdsworfhii. 

 Fig. 7 represents a small portion of the keratose skeleton of the sponge from the 

 thinnest part of the distal margin, magnified 80 linear. 



Plate VII. 



Halipliysema tubulatwm. 



Fig. 1 represents the type specimen, natural size. 



Fig. 2. The distal portion of one of the skeleton-tuhuli and its numerous ske 



leton- and defensive spicula, with the remains of, apparently, the skin 



of a minute annelid at a, and a small portion of the interstitial spicula 



at b : magnified 80 linear. 

 Fig. 3. Portions of two of the skeleton-tubuli from near the middle of their 



length, showing their loose and tortuous course, and their interior 



structure through longitudinal sections of the tubuli : magnified 80 



linear. 

 Fig. 4. One of the largest skeleton- and defensive spicula, magnified 150 linear. 

 Fig. 5. A small-sized skeleton- and defensive spiculum, magnified 150 linear. 

 Fig. 0. Two of the small subflecto-attenuato-acuate incipiently spinous defensive 



spicula, magnified 150 linear. 



3. Note on the Occurrence of Xenosponyia pateUiformis, 

 Gray, on the Coast of Ceylon. By E. W. H. Holds- 

 worth, F.L.S., F.Z.S. 



[Eeceived January 7, 1873.] 



This curious form of sponge was described and figured by Dr. 

 Gray in the 'Proceedings' of this Society in 1858, p. 229, pi. xii., 

 from two dried specimens received from Torres Straits ; and, so far as 

 I can discover, no other locality was known for it until I fortunately 

 met with a single young example on the Ceylon pearl-bank. This 

 specimen was obtained from a depth of about 8 fathoms, on a sandy 

 part of the bank ; and, knowing that an opportunity of examining 

 this sponge in as nearly as possible its natural condition was desired at 

 home, I at once put it in spirit, and on my return to England placed 

 it in the hands of Dr. Gray. 



