NATURAL HI8TORY 



I 



LETTER III. 



TO THOMAS PENNANT, ESQUIRE. 



HE ^ssil_shells of this district, and sorts of 

 stone, such, as have fallen within my obser- 

 vation, must not be passed over in silence. 

 And first I must mention, as a great curi- 

 osity, a specimen that was ploughed up in 

 the chalky fields, near the side of the Down, and giyen to 

 me for the singularity of its appearance, which, to an jn- 

 curious eye, seems like a petrified fish of about four inches 

 long, the cardo passing for a head and mouth. It is in 

 reality a bivalve of the Linnsean genus of Mytilus and the 

 species of Orista galli; called by Lister, Rastellum; by 

 Rurnphius, Ostreum plicatum minus ; by D'Argenville, Auris 

 porci, s. Crista galli; and by those who make collections, 

 cock's comb. Though I applied to several such in London, 

 I never could meet with an entire specimen; nor could 

 I ever find in books any engraving from a perfect one. 

 In the superb museum at Leicester House, 1 permission 

 was given me to examine for this article ; and though I was 

 disappointed as to the fossil, I was highly gratified with the 

 sight of several of the shells themselves in high preserva- 

 tion. This bivalve is only known to inhabit the Indian 

 ocean, where it fixes itself to a zoophyte, known by the 

 name Gorgonia. The curious foldings of the suture the 



1 This was originally the property of Sir Ashton Lever, and long 

 known as the Leverian Museum. Pennant characterized it as "the 

 most astonishing collection of the subjects of natural history ever col- 

 lected, in so short a space, by any individual." The specimens of 

 natural history and of art, which it contained, were exhibited for many 

 years, but were finally disposed of by auction, in 1806. Some idea may 

 be formed of the extent of the collection at that time by the duration 

 of the sale, which lasted for sixty -five days, and by the number of the 

 lots, which amounted to 7879. ED 



