22 SILICEOUS SPONGES. 



tests in which they have been excavated. In no instance have the spicules of the 

 boring sponge been met with. The examples are numerous. The originals of the 

 figures in the 'Annals,' vol. viii. t. 4. f. 9, 10, are in the Museum collection. 



Distribution. Upper Chalk : Norwich, Ventnor, Kent, Surrey. Drift of the Haldon 

 Hills. Miocene : Madeira. 



Cliona glomeeata, Morris, sp. 



1851. Clionites glomerata, Morris^ Ann. & Mag. Nat. Hist. vol. viii. p. 89, t. 4. f. 11. 

 This species consists of a single subglobular chamber, about 8"75 mm. in 



diameter, which has been excavated in the guard of a Belemnite. This chamber is 

 connected with the exterior by two canals, about 2 mm. in width each, as well as 

 by numerous minute thread-like stolons. The original and only specimen is in the 

 Museum collection. 



Distribution. Upper Chalk: Norwich. 



Cliona'? Mantelli, Wetherell, sp. 



1852. Clionites Mantelli,'Wet\xer€\l, Ann. & Mag. Nat. Hist. vol. x. p. 354, t. 5 c. f. 1, 2. 



This species is founded on small ovoid cavities in the shell of Inoceramus. The 

 cavities have been infilled with silica ; and by the dissolution of the shell they now 

 remain as solid bodies, of an ovoid form, 1'25 mm. in length and 1 mm. in 

 depth, disposed either irregularly or in concentric rows following the lines of growth 

 of the shell. There is no indication of any constriction at the aperture of the 

 cavities. The chambers are quite unconnected with each other ; the threads of flint 

 which Mr. Wetherell supposed to have been connecting stolons, are in reality nothing 

 more than fibres of silica which have infilled cracks in the shell of the Inoceramus. 

 The form of the cavities and their isolation from each other make it very doubtful 

 whether they have been formed by a boring sponge. The original specimens are in 

 the Museum. 



Distribution. Upper Chalk : near Bonchurch, Isle of Wight. Drift : Haldon, near 

 Exeter. 



Cliona, sp. 



Perforations by boring sponges in the shells of Cretaceous and Tertiary Mollusca ; 

 but in the absence of spicules the excavated chambers are not sufficiently characteristic 

 to determine the species. 



Distribution. Cretaceous : Pontotoc, Mississippi. Eocene, London Clay : Barton. 

 Miocene : Shurm, Sinaitic Peninsula ; Las Palmas, Canary Islands ; Porto Praya, 

 Madeira. Red Crag: Walton-on-the-Naze. 



