56 Mr. H. J. Carter on Specimens 



Ecccelonida. 



(Excavating Sponges.) 



In the ' Journal of the Koyal Microscopical Society ' (1879, 

 vol. ii. p. 496) I proposed the name of " Ecccelonida " for 

 this family, enumerating thereunder three genera, viz. Cliona, 

 Thoosa, and Alectona, and stating that the skeleton-spicule of 

 Thoosa had not been determined. Previously (' Annals,' 1879, 

 vol. iii. p. 352) I had indicated that, judging from the figures 

 which he has given, Hancock had probably based this genus on 

 spicules of some kind of Samus. I further added, in the 

 1 Microscopical Journal ' (I. c. p. 497) , that it was not impos- 

 sible that Samus anonymus would ultimately have to come in 

 as a fourth genus of the Ecccelonida. All this is now ascer- 

 tained by the undoubted excavating habit of Samus anonymus 

 in some of the Manaar nodules, and the existence of Thoosa 

 in others, where no spicule of Samus, or any thing like Han- 

 cock's figures, is present. New species of Samus have also 

 been determined, as well as more Ecccelonida, including a 

 new genus — which will now be successively described. 



Thoosa soctalts, n. sp. (PI. V. fig. 23, a-c.) 



General form (when dry and contracted) a minute sarcodic 

 mass densely charged with the spicules of the species, in which 

 no particular figure or structure can be distinguished. Colour 

 yellowish. Spicules of two forms, viz. : — 1, short, thick, 

 nodose, consisting of a central shaft upon which are developed 

 ten globular microspined projections that finally obscure it 

 from their enlargement and approximation, so arranged that 

 one occupies each extremity and the eight others two circu- 

 lar rows respectively in the centre of the shaft, all touching 

 each other when the spicule is fully developed, 8 by 5-6000ths 

 (PL V. fig. 23, a) ; 2, circular, compressed, rough or irre- 

 gularly microspined and wrinkled, 5 by 4-6000ths (fig. 23, 

 b } c) ; the latter sparsely mixed among the former. Size 

 of largest specimen about l-16th inch in diameter. 



Hob. Marine. In excavated cavities of the Melobesian 

 nodules, alone or in company with other sponges which have 

 made or have occupied them after they have been made. 



hoc. Gulf of Manaar. 



Obs. "Whether this is the sponge to which Hancock alludes 

 (I. c.) or not, he has omitted to mention its accompanying 

 spicule, viz. the cake-like one no. 2 ; while the presence of 

 the species not only by itself, but together with different 

 other sponges now occupying some of the previously ex- 



