HYALOSTELIA. 151 



name of Serpula parallela, but if such were the case, the sponge ought, by the rule of 

 priority, to retain M'Coy's specific name. I do not think, however, that the spicular 

 rods of H. Smithii are similar to those described by M'Coy, which, according to the 

 description, are only '5 mm. in thickness, whereas the majority of those found in the 

 Scotch beds are much thicker, and reach a maximum thickness of 1-5 mm. 



Distribution. Lower Carboniferous : Cunningham Baidland, Dairy, Ayrshire. Pre- 

 sented to the Museum by Dr. J. Millar, F.L.S. 



Htalostelia parallela, M'Coy, sp. 



1844. Serpula parallela, M'Coy, Synop. Carb. Foss. Ireland, p. 169, t. 23. f. 30. 

 1880. Acestra parallela, P. Roemer, Letli. Geogn. 1 Th. p. 318, f. 60. 



Straight cylindrical spicular rods, of indefinite length, and from '2 to '5 mm. in 

 thickness, disposed parallel with each other so as to form flattened bundles. The 

 surface of the rods is smooth, and the interior canal is usually preserved. The 

 originally siliceous composition has been replaced by calcite. Though no anchor- 

 shaped terminations have yet been discovered in connexion with these rods, there 

 can hardly be a doubt that they are the root-like appendages of hexactinellid 

 sponges. 



In addition to specimens from the Lower Carboniferous of Scotland, there is a well- 

 preserved example on a slab of rock, to which no label is attached, but which, from 

 its appearance and the character of the other fossils on it, seems to have been derived 

 from the Trenton Limestone at Ottawa. 



Distribution. Trenton Limestone : Ottawa, Canada. Lower Carboniferous : Cli- 

 theroe, Scotland. 



Hyalostelia fasciculus, Mj-Coij, sp. 

 1855. Pyritonema fasciculus, M'Coy, Brit. Pal. Fossils, p. 10, t. IB. f. 13. 



The only example of this species in the Museum is a thin compressed band of 

 spicular rods about 5"5 mm. in width. The rods vary from "2 to "5 mm. in thickness ; 

 the best-preserved examples show closely-set concentric transverse wrinkles, but in 

 others the surface is quite smooth. The axial canals have not been preserved. The 

 spicules in this specimen are siliceous. The transverse wrinkles distinguish this 

 species from H. parallela. 



No label is attached to the specimen ; but it appears to have been derived from the 

 Llandeilo district of Wales. 



Hyalostelia fusiformis, Hinde. (Plate XXXI. fig. 7.) 

 1880. Hyalostelia fusiformis , Hinde, Foss. Sponge-Spicules, p. 71, t. 5. f. 13-16. 

 Free hexactinellid spicules, with an elongated main axis and inflated centre. The 



