22 Transactions of the /Society. 



1878. Porosphsera globularis, Steinmann, pars. Pal?eontograpliica, toI. xxv., 



p. 120, pi. xiii., figs. 8-10. 

 1900. 71071 Po7-o^hx7-a Woodwardi, Kowe, Proc. Geol. Assoc, vol. xvi., pt. 6, 

 pp. 304, 344, 361 ; vol. xvii., pt. 1 (1901) pp. 67, 72. 



Small oval or rounded sponges, from 12 to 18 mm. in diameter, 

 with deeply impressed branching canals which extend from the 

 basal portion to the summit, and also to one or more lateral 

 centres. There is no special aperture either at the summit or at 

 the sides where these canals meet. The base of the sponge is 

 concave, elongate and rugose, and it appears to have been fixed ; 

 no spicular structure can be recognised in it. 



The surface of the sponge is covered with the apertures of 

 radial canals, which are about - 16 mm. wide and from one to 

 two diameters apart. The skeletal fibres are about 0*05 mm. in 

 thickness ; the spicules in them are now rarely visible, but here 

 and there in thin sections the pointed apical rays can be distin- 

 guished ; these are about O'll mm. in length by 0*04 mm. in 

 width at the base. 



This species, which has been fully described by the late 

 Mr. Carter, is distinguished from any of the other Chalk species 

 of Porosphcera by the strongly-marked branching canals of the 

 surface, which are very distinct from the simple, shallow grooves 

 in P. nuciformis. From this latter it differs also in the possession 

 of a concave base of attachment. 



Professor Steinmann considered that the branching canals in 

 P. Woodwardi, Carter, were of no real signification, and he included 

 the species in P. globularis, in which, however, these features are 

 not present. 



P. Woodwardi is rare, and in this country has only been met 

 with in the Grey Chalk of the zone of Holastcr siibglobosus at 

 Dover, and at Durdle Cove, Dorset. The specimens from the 

 higher zones of the Chalk, which have been referred by Dr. Eowe 

 and others to this species, really belong to P. nuciformis. Stein- 

 mann also states that this species occurs in the Upper Chalk 

 (Senonian) of Vordorf and Ahlten, North Germany, but it is pro- 

 bable that the forms mentioned should be included in P. nuciformis. 



Porosphcera pileolus (pi. I., figs. 20-21a; pi. II., fig. 5). 



1829. Lii7i7ilites urceolata, Phill. (non Lamarck), Geol. Yorks., pt. 1, p. 186, 



pi. i., fig. 11. 

 1854. Cosct7iopora (?) pileolus, Morris, Cat. Brit. Foss., 2nd ed. p. 28. 

 1860. Orbitolina concara, Parker and Jones (non Lain, sp.) Ann. and Mag. 



Nat. Hist., ser. 3, vol. vi., pp. 35, 39. 

 1875. Coscinopora pileolus, Etheridge (Phill.) Geol. Yorks. 3rd ed. p. 322, pi. i., 



fig. 11. 

 1900. Po7-osphxi-a pileolus, Eowe, pars. Proc. Geol. Assoc, vol.xvi., pt. 6, pp. 304, 

 344, 361 ; vol. xvii., pt. 1 (1901) pp. 67, 72. 



