4 



BRITISH FOSSILS. 



Locality and Geological Position. Our specimens in the Museum 

 of Practical Geology were collected during the researches of the 

 Survey at Steeple Ashton and near Abbotsbury Castle, in both 

 instances in the Coral rag. Dr. Wright's examples were collected 

 ^'from the yellow clays and ragstones of the Coralline Oolite in 

 Wilts.'' The specimen described by M. Jules Haime came from the 

 Coral rag near Malton. 



Description of Plate III. 

 Figs. 1. 2. and 3. Views of the original specimen upon which Milnea decorata was 

 founded. 



Fig. 4. A magnified view of the apical disk of the same specimen, in which, in con- 

 sequence of the very narrow and abnormally semi-lunar posterior genital 

 plate, and the loss of the anterior sur-anal plates, a large and ovate vent 

 appears to belong to the posterior ambulacral segment. It was this appearance 

 that misled M. Haime. 



Fig. 5. Portion of the under surface highly magnified, showing the triplication of the 

 pairs of pores near the mouth, and the deep notches with reflected 

 margins. 



Fig. 6. Ambulacral and interambalacral plates of the surface near the disk. 



Fig. 7. Similar plates from the centro-lateral region of the segments. 



Fig. 8. A primary tubercle with its crenulated boss. 



Fig. 9. Primary spines of the natural size. 



Fig. 10. The base of a primary spine magnified. 



Fig. 11. Magnified view of a secondary spine. 



Fig. 12. A plate from the disk. 



Fig. 13. Outline of a very complete disk (from a specimen communicated by 

 Dr. Wright). 



JVoie on undescrihed species of Aceosalenia. 



1. Acrosalenia pustulata, sp. nov. 



A. ambulacris angustis, tuberculis parvis in seriebus duobus approximatis subalternatis 

 dLspositis ; interambulacrorum tuberculis centro-lateralibus magnis, superioribus minutis ; 

 areolis disjunctis ; area centrali angustissima, bigramolata, granulis sparsis. 

 Diam. ^ unc. Alt. ^ unc. 



It resembles A. decorata, and holds a position between that species and A. Wiltoni. 



The spines are very long, slender, and apparently smooth. (Mus. Pr. Geol.) 

 Locality. The Forest marble of Malmesbury. 



2. Acrosalenia radiata, sp. nov. 



A. ambulacris angustis, tuberculis parvis seriebus duobus approximatis alternatis 

 sub-divergentibus dispositis ; interambulacrorum tuberculis numerosis regulariter graduatis, 

 superne decrescentibus centro-lateralibus mediocribus, areolis disjunctis; area centrali 

 angusta paucigranulata, granulis sparsis. 

 Diam. unc. Alt. ^ unc. 



It has affinities with A. spinosa, but differs in having the primary tubercles regularly 



diminishing instead of suddenly decreasing above. (Mus. Pr. Geol.) 

 Locality. Collected by Mr. Lycett in the Great Oolite of Minchinhampton. 



Edward Forbes. 



October, 1852. 



