640 DR. G. J. HINDE AND MR. HOWARD EOX ON [Nov. 1895, 



spines '25 mm. No structure is shown, and it is doubtful whether 

 it rightly belongs to this genus. Not uncommon. Ramshorn Down. 



Trigonocyclia ? sp. b. PI. XXVI. fig. 12. Test subtriangular in 

 outline, the sides curved. Diameter of disc "21 mm. ; length of 

 spines - 2 mm. No structure preserved. Ramshorn Down. 



Genus Porodiscus, Haeckel. 



Discoidea without phacoid shell; with a fiat discoidal shell, in 

 which a simple spherical central test is surrounded by concentric 

 chambered rings (each ring divided by radial beams into imperfect 

 chambers). Surface on the two flat sides covered by a porous sieve- 

 plate ; the margin simple. 



Porodiscus lens, sp. nov. PI. XXVII. fig. 10. As shown in 

 section the test is elliptical, with a long diameter of *14 mm. and 

 transverse "095 mm. ; the central chamber is - 06 mm. in width. It 

 has two rays diverging from an excentric point to its margin, and 

 it is surrounded by two chambered rings, partitioned off by numerous 

 rays. The surface-pores are not shown. Not uncommon. Hedge- 

 section at Lawell House, Chudleigh. 



Porodiscus brevis, sp. nov. PI. XXVII. figs. 2, 3. Test elliptical 

 to nearly circular in outline, diameter *13 to # 15 mm. ; central 

 chamber relatively large, diameter *08 mm. "Within it are four 

 beams radiating from an excentric point, and it is surrounded by one 

 or two rings divided by radial beams. This form differs from the 

 preceding in the larger size of the central chamber and the less 

 development of the rings. Hedge-section at Lawell House, Chud- 

 leigh. 



Porodiscus percinctus, sp. nov. PI. XXVII. figs. 1, 11. Nearly 

 circular in outline ; diameter -25 mm., with wide central chamber, 

 •08 mm. in diameter, surrounded by about seven concentric cham- 

 bered rings of approximatively equal width. Radial beams nume- 

 rous. The surface-pores not shown. Pig. 11 is a vertical section, 

 probably of this species. Common at Ramshorn Down ; in the 

 hedge-section, Lawell House, near Chudleigh ; and at Bishops- 

 teignton. 



Porodiscus sp. a. PI. XXVII. fig. 13. This is a vertical section 

 of a similar form to the preceding, but it is larger ; the central 

 chamber is "09 mm. in width, and there are from seven to eight 

 chambered rings. Ramshorn Down. 



Porodiscus clathratus, sp. nov. PI. XXVII. figs. 4, 12. The 

 discoid test, of medium size, is -18 mm. in diameter; the central 

 chamber is "06 mm. in width. It is surrounded by four concentric 

 chambered rings ; the innermost is wider than the others. The 

 radial beams are numerous. In fig. 12 the outer porous test is 

 shown. Not infrequent. Ramshorn Down. 



