Mr. J . Mon-is's Pakeontological Notes. 89 



touched, and, notwithstanding these attacks, still equally adapted 

 to every purpose requii'ed by the oeconomy of its inhabitant." 



We have given some illustrations of the most abundant spe- 

 cies, Clionites Conybearei*, one (fig. 8) in which the siliceous casts 

 of the cavities cover almost entirely the surface of an Inoce- 

 raraus — a specimen presented by Mr. R. A. Austen to the Mu- 

 seum of Practical Geology. Fig. 9 is a specimen filling a por- 

 tion of the cast of a Belemnite from Norwich ; fig. 10 shows sim- 

 ply the cavities left in the shell of an Inocei-amus from Northfleet, 

 Kent. Another species in a Norwich chalk-flint, C glomerata 

 (fig. 11), which appears to be distinct from the last, consists of 

 one cell having an irregular globose form, obtusely tuberculated 

 over the whole surface, and ha\ing two large canals diverging 

 from it. 



Pearl-like bodies. — Most persons are aware that some forms of 

 the conchiferous moUusks are subject to certain abnormal se- 

 cretions, assuming a more or less regiilar form, and composed 

 of fibro-calcareous matter generally arranged in a concentric 

 manner ; sometimes it is solidly attached to the inner layer of 

 the shell, of which it forais a portion ; at others it is found per- 

 fectly free in the fleshy substance of the mollusk itself, of a sym- 

 metrical shape, as in the perfect pearl. Evidence of phsenomena 

 resulting from similar conditions has been detected in certain 

 fossil genera, but few if any instances have been recordedf. The 

 collection of Mr. Wetherell contains many illustrative speci- 

 mens ; in one, a Gryphaea (fig. 16) from the di-ift of Muswell 

 Hill, and probably coming from the Oxford clay, is an irregular 

 elongated body free at both ends, but attached by a considerable 

 portion of its surface, the external lamina being continuous wuth 

 the shell; the outer layers do not however show the regular 

 fibrous arrangement of a pearlaceous body, but this may have 

 been changed by subsequent mineralization. In another speci- 

 men (fig. 12) the pearly body is attached to the interior of an 

 Inoceramus, and shows the concentric arrangement of the fibrous 

 substance, and which is better exhibited in the specimen (fig. 14), 

 showing a complete section of one of considerable size, quite un- 

 attached to any shell, from the Chalk of Kent, but from which 

 Mr. Wetherell has obtained a few other specimens of similar struc- 

 ture, varying in their dimensions. 



* Clionites Conybearei ; cells irregular, somewhat polygonal, with one or 

 more papilla: ; surface finely tuberculated ; connecting threads numerous. 

 (References: Park. Org. Rem. pi. 8, f. 10; Dr. Mantell's Pictorial Atlas, 

 pi. 40. f. 10.) 



t There is an indistinct allusion to the occurrence of pearls in a fossil 

 state, in Woodward's ' Essay towards a Natural History of the Earth,* 1695, 

 p. 23. 



