86 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Juiie 14, 



abdominal areas was very rarely exhibited, in consequence of the in- 

 tersections being necessarily more or less oblique ; and it was fre- 

 quently obscured, especially to^Yards the lower part of the specimen 

 figured, by the intervention of portions of lamellge with a still more 

 intricate cellular composition. The sides of the cavities sometimes 

 presented traces of a vertical wall, or a nearly even plate, the at- 

 tenuated edge possibly of a lamella ; but the boundary consisted very 

 often of curved laminae, belonging clearly to the cells which formed 

 the bodv of the lamellse. Occasionally (fig. 13(*)) a cavity displayed 

 proofs of the polype-membranes having been lacerated, and for a time 

 intermingled, the side-structure being for a limited distance defective 

 or wanting, and the transverse laminse apparently extended into the 

 lamellated area. Other instances of abnormal development were 

 noticed. 



In considering the characters of the lamellae, the perfect exteriors 

 first claim attention. The beautiful specimen from Red Hill (fig. 14) 

 already mentioned, and another equally fine, presented to the Geolo- 

 gical Society by Mr. Warburton or Mr. Austen, if hastily compared 

 with Atherfield casts, might be regarded as specifically distinct. The 

 outline of the component structures, instead of being broad and 

 rounded, was relatively narrow and crested, with more or less of 

 interspace ; but the number of the lamellae as well as their detailed 

 arrangement was similar in each case ; a part also of the Red Hill 

 specimen, slightly abraded, exhibited a considerable increase of 

 breadth. The whole exterior of the perfect coral-layer was rugose 

 or papillated ; and the surface of the portion on the sides of the 

 abdominal cavities was minutely perforated. That no specific dif- 

 ferences existed between these specimens and those found at Ather- 

 field will, it is hoped, be established by the following statements. 

 A Peasemarsh coral (fig. 15), found by Mr. Austen, preserved also 

 its original substance ; but the structure was in an immature state, 

 presenting narrow ridges and hollows, the animal having been 

 destroyed while a probably periodical addition was in progress. 

 The ridges bore the semblance of ordinary lamellae ; but some of 

 those which had been accidentally broken showed that they were 

 not portions of vertically continuous plates, the subjacent exposed 

 substance consistmg of pale brown calcareous spar ; and fractured, 

 attenuated edges of prominent lamellae, subdivided, where the thick- 

 ening commenced, into two plates, which diverged to the right and 

 left. The riclges therefore must not be regarded as simple lamellae, 

 similar to those which occur in Siderastrcea galaxea ; nor must the 

 intermediate depressions be considered the equivalents of the qua- 

 drangular network in that coral ; the whole presenting the rudiments 

 of a fabric, and not a perfected construction, as in the recent species. 

 An Atherfield specimen, given to the Geological Society by Mr. War- 

 burtoUj exhibited casts of a perfectly similar structure to that of the 

 Peasemarsh example ; and a comparison of it \Aith an equally im- 

 mature portion of one of the broad casts from the former locality, 

 proved that the three compositions were essentially identical. Inter- 

 mediate stages between the condition exhibited by the Pcasemarsl\ 



