162 BRITISH PALAEOZOIC SPONGES. 



the anchoring-spicules on a slab of dark limestone, which he regarded as identical 

 with the groups of annelid tubes described by Goldfuss as Serpula socialis. Sub- 

 sequently M'Coy disputed the identity of the specimens with Goldfuss's species ; 

 but, accepting their annelidan characters, changed the name to Serpula parallela. 

 Professor Suess of Vienna appears to have first called attention to the real character 

 of the spicular bundles, by comparing them to the anchoring-ropes of the recent 

 Hyalonema. 



Hitherto only the bands of anchoring spicules have been included in this 

 species, but I have discovered on the slab of limestone containing Portlock's 

 typical anchoring-spicules, a single modified hexactinellid spicule of the same 

 character as those discovered by Mr. J. Wright, associated with the anchoring- 

 spicules in the decayed chert of Ben Bulben ; and there seems, therefore, good reason 

 to suppose that these five-rayed dermal spicules belong to the same Sponge as the 

 anchoring-spicules . 



This species differs from Hyalostelia Smithii, not only in the form of the dermal 

 spicules, but the anchoring-spicules are considerably smaller. Whilst in H. Smithii 

 the majority of the spicules range from - 7 to 1*4 mm. in thickness, in the present 

 species they seldom exceed '5 mm. in thickness. They closely correspond in size 

 with H. fasciculus, M'Coy sp.,but in no instance have I seen any of the transverse 

 rods or frills which characterise this latter species. 



Distribution. — Carboniferous Limestone : Clitheroe, Lancashire ; Yoredale 

 series, Gunnerside Gill, Muker, Richmond, Yorkshire ; Henblas, Gwydfyd, Great 

 Ormes' Head, North Wales. 



Scotland. — Beith, Ayrshire ; Hillhead and Whitfield quarries, near Macbiehill 

 Station, Peebles; shale above No. 1 Limestone (R. Etheridge, junr.). 



Ikeland. — Calp or Middle Limestones : Ballinhillick, Bundoran, Co. Leitrim ; 

 Clogher, Tyrone. Upper Limestones : Ben Bulben, near Sligo. 



Genus. — Holastekella, Garter, emend. Rinde. 



1879. Ann. and Mag. Nat. Hist., ser. 5, vol. iii, p. 141. 



Generic Characters. — Massive club-shaped Sponges, supported on a sub-cylin- 

 drical stem. The body of the Sponge apparently traversed longitudinally by 

 sinuous canals. The skeleton consists of comparatively large, regular, hexactinellid 

 and other spicules, mingled with smaller stellate and globostellate forms. The 

 larger spicules are disposed irregularly ; some of their rays appear to be partially 

 fused with those of adjoining spicules, probably resulting from fossilization, whilst 



