4 



BRITISH FOSSILS. 



Fig. 7. A portion of the lateral fasciole, with the neighbouring surface, much 

 magnified. 



Fig. 8, Tubercles and granules of the dorsal surface, magnified. 

 Fig. 9. Tubercles and granules from under surface. 



Fig. 10. Large tubercles and granules of the margins of the anterior sulcus. 

 List of British Species of Cardiaster. 



1. Cardiaster granulosus. (Described in this Decade.) 



2. Cardiaster excentricus. (Described in this Decade.) 



3. Cardiaster rostratus. (Described in this Decade.) 



4. Cardiaster pygmceus, Forbes. Ann. Nat. Hist. 2d ser., vol. vi. p. 444. (noticed only.) 



C. minutus, ovatus, ambitu cordato, amhulacris tuberculisque inconspicuis, 

 dorso suh-carinato, ano alto. 

 This little species is common in the Chalk of Dover, where good specimens have 

 been found by Mr. C. F. Cockburn, and presented by that gentleman to the Museum 

 of Practical Geology. The ovate outline, apparently smooth surface (under the lens 

 scattered primary tubercles are seen among minute granules), simple and narrow 

 poriferous avenues, strongly carinated anteal sulcus, subcarinated posteal segment, 

 and high posterior truncation with the vent at the upper part, strikingly characterize 

 it. A middle sized specimen measures ths of an inch in length by — ths in 

 breadth, and ^ ths in height. Its proportions vary considerably. 

 All the above are from the White Chalk. 



5. Cardiaster suhorhicularis of Defrance, Brongniart, and Goldfuss (under the genus 

 Spatangus). This is the Holaster carinatus of Agassiz. In the Catalogue Raisonne this 

 name is made synonymous with Spatangus nodulosus of Goldfuss and Spatangus planus 

 of Mantell, but the former appears to me to be the Holaster Icevis of Brongniart, and the 

 latter to be perfectly distinct from either. 



Of Cardiaster suhorhiculains I have seen only one British specimen, which on 

 comparison with French examples appears to be truly referable to this species. It 

 is from the Upper Greensand of the neighbourhood of Osmington in Dorsetshire, 

 where it was obtained by Mr. E. H. Bunbury, who presented it (as part of his 

 fine cretaceous collection) to the Museum of Practical Geology. 



6. Cardiaster fossarius. The Spatangus fossarius of Miss Benett. This is the 

 Holaster Greenoughii of Agassiz. With us it occurs in the Upper Greensand of War- 

 minster. 



7. Cardiaster bisulcatus. In the Museum of Practical Geology \h.m^ is a Cardiaster 

 from the Greensand of Blackdown, remarkable for the small tubercles in proportion to its 

 size, and the great width of the hinder lateral poriferous avenues. It seems to be 

 identical with the Holaster bisulcatus described and figured by M. Albin Gras in his 



Oursins fossiles de ITsere," p. 62, pi. 4, fig. 7. 8. He obtained it from the Gault of Ravix. 



8. Cardiaster Benstedis, sp. nov. 



In the Lower Greensand of Maidstone several examples of an urchin apparently a 

 true Cardiaster have been found, distinct from any of our other species. It may be 

 characterized thus : 



c. late cordatus, subhemisphcericus, dorso rotundato, seriebus pororum 

 omnibus angustis subequalibus. 



The anterior sulcus is strongly marked and wide below. The back is gently 

 curved. The vent is medial in position as compared with the height. The pori- 

 ferous avenues are all remarkably narrow, and the hinder ones as broad as the antero- 

 laterals. The surface of the test is too imperfectly preserved to be described. 

 Specimens have been presented to the Museum of Practical Geology by Mr. E. H. 

 Bunbury and Mr. Morris. 



October J 1852. Edward Forbes. 



