PLATE VII. 



Figs. 1, la — 1 g. — Tholiasterella gracilis, Hinde, sp. nov. 



Figs. 1, 1 a, 1 b. — Fragments of the dermal layer of the Sponge, showing the 

 inner surface, and the mode in which the horizontal rays of the spicules are inter- 

 laced, and partially fused together. The vertical rays of the spicules are directed 

 towards the interior of the Sponge. Enlarged ten diameters. From the Lower 

 Carboniferous, upper part of the Lower Limestone series at Law Quarry, Dairy, 

 Ayrshire. Tbe original specimens in the collection of Mr. John Smith, Kil- 

 winning. 



Figs. 1 c — 1 g. — Detached spicules referred to the same species. In 1 c, 1 d, 

 the inner or under surface of the spicule is shown, and in 1 e, If, 1 g, the outer or 

 upper surfaces ; whilst in 1 h, the spicule, showing the vertical ray, is seen in profile. 

 All enlarged ten diameters. From the same horizon and locality as the preceding. 



Figs. 2, 2 a — 2/. — Tholiasterella Yotjngi, Hinde. 



Figs. 2, 2 e. — Fragments of the dermal layer of the Sponge, showing the inner 

 or under surface and the interlacing of the spicules. Enlarged ten diameters. 

 From the same horizon and locality as the preceding. 



Figs. 2 a — 2 d, 2f. — Detached spicules referred to the same species. In 2 a, 

 2f, the under surface of the spicules is shown ; in 2b, 2c, the upper surface ; 

 whilst 2 d is seen in profile. The original specimens in the collection of Mr. John 

 Smith. 



Figs. 3, 3 a. — Tholiasterella cohpacta, Hinde, sp. nov. 



Fragments of the dermal layer of the Sponge. Fig. 3 shows the inner surface, 

 and the mode in which the spicular rays are completely fused together. The 

 vertical or entering rays of the spicules are broken off, and only their truncated 

 bases remain. Fig. 3 a shows the upper or outer surface of another fragment. 

 Enlarged ten diameters. From the Lower Carboniferous at Law Quarry, Dairy, 

 Ayrshire. 



The original specimens in the collection of Mr. James Bennie. 



