Mr. W. Lonsdale on the Genus Lithostrotion. 475 



The figures there given have a general resemblance to each 

 other, presenting an inner and an outer area ; and they agree 

 with Lhwyd's delineation in their numerous rays or lamella? ; but 

 Guettard' s fossil in the opinion of De France (op. cit. t. xlii. 

 p. 384) had a centre or " axis *," which resisted the action of the 

 weather, and gave rise to what Guettard terms "un couvercle" 

 (Mem. t. iii. p. 510). This character would agree possibly with 

 what Parkinson says respecting the centre of his Lithostrotion 

 (Org. Kem. t. ii. p. 44), but not with Dr. Fleming's " small, 

 solid, central axis" (Brit. Anim. p. 508), or with the " columelle 

 styliforme" and " columelle petite " of the 'Archives' (Car. gen. 

 p. 432 ; and Car. spec. p. 442) ; nor is such a structure exhibited 

 in figure 2. pi. 52 (Mem.). In Parkinson's brief notice (Org. 

 Hem. t. ii. p. 41) of the coral referred to by De France, no struc- 

 tural details are mentioned ; but the figure (pi. 5. f. 1) was taken 

 from a Swedish specimen, and the fossil is conjecturally iden- 

 tified with the Baltic fossil represented by Fougt f, and subse- 

 quently named by Linnaeus J Madrepora ananas — points which 

 necessarily excite doubts respecting a specific agreement with 

 Lhwyd's fossil. It is regretted that the data are not given for 

 associating Astrea arachndides with Lhwyd's Lithostrotion and 

 Dr. Fleming's L. striatum ; the remarks of De France and those 

 of the authorities quoted by him being insufficient to satisfy an 

 inquirer. Moreover the specimen from which the figure given in 

 the ' Memoires ' and the accompanying explanation were derived, 

 was obtained from Chaumont near Anvillers, three leagues from 

 Verdun, a district believed to be geologically of the age of the 

 oolites. It is possible however that the identification is with the 

 smaller variety of Guettard's fossil mentioned only by De France, 

 and found at Valogns (Manche) " dans les couches anciennes " 

 (op. cit. p. 384). Nevertheless it would be satisfactory, had a 

 note been given to fix the association with Guettard' s original 

 fossil or with De France's variety, as well as to define the loca- 

 lity and formation. 



The chief distinction in the detailed specific and generic struc- 

 tures is the non-allusion in the former to central transverse 

 lamina? or " planchers bien developpes" (Car. gen. p. 432) ; and 



* " Ce morceau, dont la surface paroit avoir ete detruite, presente, ainsi 

 que le dit Guettard, un couverele au milieu de chacune des etoiles ; mais ce 

 couvercle n'est autre chose qu'un axe, qui, ayant presente plus de solidite 

 que les rayons, se trouve eleve un peu au dessus d'eux." — Diet. Sc. Nat. 

 t. xlii. p. 384. " Ce morceau " alludes to a specimen in De France's pos- 

 session. 



t Dissertatio de Coralliis Balticis apud Amcen. Acad. t. i. p. 195, and 

 illustrative plate, figs. 9, 8. Parkinson quotes only fig. 8 and the diagram 

 No. 2. 



X Svstema Naturtc, edit. 10. t. i. pi 797, No. 35. 



