PLATE XXIV. 



Page 

 Fig. 1. Stauronema Carteri, Sollas. The lower portion of an imperfect specimen from 



the Upper Green Sand at Cap la Heve, near Havre, showing the inner concave 



surface. Natural size 99 



Fig. 1 a. The same. Showing the convex outer surface of the same specimen. 



Fig. 1 b. The same. Portion of the spicular mesh of the interior of the wall. Enlarged 

 thirty-two times. 



Fig. 2. Stauronema planum, Hinde. The upper surface of a specimen, showing the canal- 

 apertures, which in places are partially obscured by a delicate dermal layer. 

 Natural size. From the Grey Chalk near Folkestone 100 



Fig. 2 a. The same. The under surface of part of fig. 2. Natural size. 



Fig. 2 b. The same. A vertical median section of the same specimen, showing traces of the 

 canals and the spicular mesh. Natural size. 



Fig. 2 c. The same. Portion of the polished surface of 2 b. Enlarged thirty-two times. 

 The dark lines forming the squares represent the canals of the mesh-spicules, 

 which have been infilled with an opaque material, probal)ly peroxide of iron. 



Fig. 3. Verrucocoelia vectensis, Hinde. From the Chalk Marl at Ventnor, Isle of Wight. 



Natural size 98 



Fig. 3 a. The same. Portion of the outer siirface of fig. 3, enlarged thirty-two times, 

 showing the structure of the dermal layer. 



Fig. 3 b. The same. Portion of the spicular mesh of the interior of the wall. Enlarged 

 thirty-two times. Drawn from a fractured surface of one of the projecting 

 tubes. 



