104 FOSSIL ASTBROIDBA. 



Material. There is only one specimen of this species. This is preserved in 

 the British Museum (Nat. Hist.), and bears the registered number E. 5052 

 (purchased of Simmons). 



Description. The disc is about 15 mm. in diameter. It is covered with a large 

 number of small plates, which are rather scattered. The arms are 3 mm. broad 

 at the base. The upper arm-plate is much narrower than in 0. serrata. There 

 are five spines, about three quarters the length of an arm-segment, on each side 

 of the arm. 



Locality and Stratigraphical Position. Upper Chalk, Bromley, Kent. 



Genus OPHIOTITANOS, 1 novum. 



Disc covered with plates which are small and sub-equal. Radial shields small, 

 triangular, naked, scarcely swollen. Arm-spines small. Mouth-shields large. 

 Side mouth-shields small, widely separated. 



1. OPHIOTITANOS TENTHS, n. sp. PI. XXVIII, figs. 1, la, 2, 2 a. 



Proximal upper arm-plates longer than broad. . Spines very short, five in 

 number. Disc, with the exception of the radial plates, covered with an extensive 

 granulation. 



Material. The material for the description of this species consists of several 

 specimens in the British Museum (Nat. Hist.), The specimen E. 5056, which is 

 the type, is figured on PL XXVIII, fig. 1, and the specimen E. 5057 on PI. XXVIII, 

 fig. 2. There are also specimens registered E. 5058, E. 5059, 57512. All are in a 

 fair state of preservation. The first four specimens are from the Capron Coll., 

 and the latter specimen was purchased from W. Griffiths. There are further 

 examples of the species in the Sedgwick Museum, Cambridge. 



Description. The disc is flat on the dorsal surface, and its diameter in the 

 largest specimen is 4*7 mm. Each pair of radial shields is separated by three 

 ornamented plates. 



The mouth-shields are almost oval in shape. The side mouth-shields are 

 small, and lie widely separated on the outer edges of the mouth-shields. Them 



e = chalk. 



