164 BRITISH PALEOZOIC SPONGES. 



42. Holasteeella comferta, Garter. Plate VIII, figs. 2, 2 a — 2 g. 



1879. Holasteeella coneerta, Carter. Ann. and Mag. Nat. Hist., ser. 5, 



vol. iii, p. 141, pi. xxi, figs. 1, 2, 8, 

 cet. excl. 



1883. JYon — — Hinde. Cat. Foss. Sponges, p. 152, pi. xxxii, 



figs. 2-2/ 



The typical example of the species is a club-shaped Sponge, about 165 mm. in 

 height by 50 mm. in extreme width. It gradually increases in thickness from its 

 base to the rounded summit. The Sponge is broken into several pieces, and its 

 form is to such an extent enveloped and concealed by the matrix, that I have not 

 attempted to figure its outline. 



The canals which apparently traverse the Sponge longitudinally are sinuous in 

 their course, and from *5 to "8 mm. in width. The surface of the Sponge is also 

 excavated by numerous ovoid or wedge-shaped pits from 1 to 1*5 mm. in length ; 

 some of these extend but a short distance into the Sponge, and exhibit smooth 

 sides. They are regarded by Mr. Carter as the burrows of crustaceans. 



The minute stellate and globo-stellate spicules occur in small groups on the 

 surface, and in the interior of the Sponge ; their rays terminate obtusely. They 

 have an average diameter, including the rays, of '3 mm. The rays of the smaller 

 hexactinellid spicules, which partly compose the body of the Sponge, are about *3 

 mm. in length ; whilst in some of the larger spicules, which are only partially shown, 

 the rays reach to 2*3 mm. in length by '3 mm. in thickness. The spicules and 

 fragments figured on PL VIII, figs. 2 — 2 g are drawn from the type-specimens 

 forwarded to me by Mr. J. Thomson and by Mr. Carter, and they are the most 

 perfect which could be found in them. 



Distribution. — Carboniferous : highest beds of Upper Limestone of the South- 

 west of Scotland, near Glasgow (J. Thomson). 



Genus. 1 — Spiractinella, Hinde, gen. nov. 



Syn. — Holasterella (in part), Garter, Hinde. 



Form of Sponge unknown, it is composed of simple hexactinellid spicules, and 

 forms derived from them, which apparently were quite free from each other, and 

 merely held in position by the soft structures of the Sponge. The simple hexac- 



1 lirelpa, anything wound round; o/cnV, ray, dimin. 



