THE ANNALS 



AND 



MAGAZINE OF NATURAL HISTORY, 



[FOURTH SERIES.] 

 No. 71. NOVEMBER 1873. 



XLIV. — On the Hexactinellid^e and Litkistid m generally, 

 and -particularly on the Aphrocallistidae, Aulodictyon, and 

 Farreas, together with Facts elicited from their Deciduous 

 Structures, and Descriptions respectively of Three Neiv 

 Species. By H. J. Carter, F.R.S. &c. 



[Plates XIIL-XVIL] 



This paperwas commenced with observations on some deciduous 

 specimens of the Hexactinellidas from the deep sea, in which 

 the influence of an absorbing process (to be mentioned here- 

 after) had rendered the sexradiate spicules, on which the 

 vitreous fibre had originally been deposited, again recognizable. 

 It was then found necessary to study the Hexactinellidge and 

 Lithistidae (that is, Dr. J. E. Gray's Coralliospongia ex parte) 

 generally for a better understanding of this process, and par- 

 ticularly the Aphrocallistidw, Aulodictyon, and the Farrem, as 

 it was in the deciduous fibre of such sponges that the facts 

 desired were, if possible, to be ascertained. During this study 

 much information hitherto unknown has been obtained, and 

 three new species of vitreous sponges discovered. 



I shall first, therefore, give the results of my investigations 

 of Dr. Gray's Coralliospongia &c, under the heads respectively 

 of " Hexactinellidse " and " Lithistida? " — afterwards an ac- 

 count of the specimens respectively to which I shall have to refer 

 when the spicules of the Aphrocallistidaz, Aulodictyon, and 

 the Farreos in the living state have been described and I 

 come to the identifying of them in the deciduous structures — 

 and, lastly, a short summary of what these structures have 



Ann. & Mag. N. Hist. Ser". 4. Vol. xii. 24 



