EXPLANATION OF THE PLATES AND WOOD-CUTS. 



From the above characters, believed to be new among lamelliferous corals, it is 

 inferred that this fossil does not belong to the genus Porites ; but it has been thought 

 advisable not to propose, at present, a new one for it. 



Loc. Newton Bushel, Marychurch, Plymouth, &c. 

 Figs. 5 to 5 d. Coscinopora placental (Goldfuss, PI. IX. f. 18.). 



Prof. Goldfuss described the fossil which he has called Coscinopora placenta from 

 apparently a single and probably an imperfect specimen, and was therefore unable 

 to detail fully its characters. It is with considerable hesitation that the Devonian 

 fossil has been assigned to the same genus and species ; but it has been thought 

 better to do so provisionally than to propose a new generic appellation. 



The coral represented in Figs.5to 5d. consists of amorphous masses, composed of 

 very thin concentric layers, traversed horizontally and obliquely by irregular vermi- 

 form cavities, and perforated vertically by cylindrical tubes, which penetrate the 

 whole depth of the specimen, and are bounded by a white circle forming the sub- 

 stance of the tube (Figs. 5, 5 a. 5 b. 5 d.). The distance between the layers is 

 about equal to their thickness ; and the layers are united by vertical filaments of 

 variable form and dimensions, the interstices having a punctured appearance (Fig. 

 5 a.). In some specimens the vertical section is banded, being crossed by stripes 

 of a darker colour (Fig. 5a.). 



This fossil varies greatly in character, according to its state of preservation or 

 mineralization. In some specimens, all structure has nearly disappeared, except 

 the vertical tubes, and the coral then agrees with Goldfuss's description (C. dis- 

 coidea, poris orbiculatis cequalihus, interstittis Icevibus). Other specimens might 

 be mistaken for masses of Stromatopora concentrica, except that the tubes with 

 careful search may always be found (Figs. 5 b. 5 c. 5 d.) ; and the resemblance is 

 still stronger in some masses consisting of gray carbonate of lime, traversed at 

 distant intervals by concentric bands of the decomposed coral. 



Loc. Newton Bushel, Torquay, Appleway, Plymouth, &c. 

 Petraia (Munster, MS.). 

 Fig. 6. Petraia Celtica. 



Turbinolia Celtica (Lamouroux, Expos. Method. PI. LVIII. f. 7, 8.). (See ante, 

 p. 697.) 



Turbinated ; external cast smooth ? ; internal cast composed of thick lamellfe, 

 with two indistinct rows of papil]£e and a furrow down the middle. 



An abundant coral in the slate rocks of Cornwall, but it rarely presents more 

 than flattened casts of the interior. It is placed in this genus because it agrees 

 generically with specimens labelled Petraia from the continental collection of 

 Count Munster. 



Loc. Dinas Cove Padstow, Berry Pomeroy, and Fowey. 



A large coral differing from the above, principally in size, occurs in slate rocks 

 at New Quay, and near Newton Bushel. 

 Fig. 7. Strombodes vermicular is. 



Cyathophyllum vermicular el (Goldfuss, Petref. Tab. 17, f. 4.). 



Cylindrical, straight or curved, externally traversed by vertical ridges, marking 



