MASTOSIA.— HINDIA. 57 



Genus MASTOSIA, Zittel, 1878. 



Mastosia neocomiensis, Hinde, n. sp. (Plate X. fig. 4.) 

 The only representatives of this species are detached spicules, which occur in green- 

 sand strata, mingled with spicules of tetractinellid sponges. The spicules in question 

 have a spherical or slightly elongated centre, from which three to five short cylindrical 

 arms project. The arms radiate irregularly from the central node, and are slightly 

 expanded at their ends. The central node averages -2 mm. in thickness, and the 

 arms are "225 mm. in length. These spicules are distinctly typical of the Anomo- 

 cladine family; and though up to the present no sponge belonging to this family has 

 been recognized from the Cretaceous series, the occurrence of these spicules clearly 

 proves their existence in this period. 



Some of the s^jicules described and figured by Mr. H. J. Carter from the Upper 

 Green Sand of Devonshire as " knots or branching centres of silicified fibre like that 

 oi Dactylocalyx"* evidently belong to this species. 



Distribution. Lower Green Sand : Haslemere, Surrey. Upper Green Sand : Devon- 

 shire [Mr. II. J. Carter). 



Genus HINDIA, Duncan, 1879. 



HiNDiA FIBROSA, Fetd. Roemer, sp. (Plate XIII. figs. 1, 1 a, 1 b.) 



1860. Calamopora fibrosa, F. Roemer (non GoldfiLss), Die silurische Fauna d. westl. Tennessee, 



p. 20, t. 2. f. 2, 2 a, 6. 

 1875. Spheerolites Nicholsoni, Hinde, Abstract of the Proc. Geol. Soc. no. 30.t. 

 1875. Hindia spheroidalis, Duncan, Ann. & Mag. Nat. Hist. 5 ser. vol. iv. p. 84, t. 9. 



Sponges globular in form, with an even rounded surface, and without peduncle 

 or any point of attachment. The specimens vary between 13 mm. and 3S mm. in 

 diameter. 



As seen in a section through the centre, the growth of the sponge commences with 

 a small foreign body or even loose tissue in the centre, from which extend minute 

 straight canals about "3 mm. wide, in close proximity to each other, to the outer 

 surface. The canals are circular or polygonal in section ; their walls are formed by 

 the spicular skeleton. The individual element of the skeleton appears to have a 

 thickened subspherical centre, from which four to six short arms radiate in different 

 directions, and by their attachment to the ends of adjoining spicular arms form a 

 continuous, open, very regular mesh. The spicular arms or rays appear to be' either 

 smooth or tuberculated. No special surface-spicules have been preserved. 



Examples of these sponges occur in different states of preservation. Those from 

 Tennessee, which F. Roemer placed under Calamopora, are silicified, the spicular 



* Annals & Mag. Nat. Hist. vol. vii. 1871, t. 7. f. 13, 14, and t. 8. f. 23. 



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