140 Mr. Reeve on a new Glassy Nautilus. 



XX. — Description of a new species of Carinaria, a genus of 

 Nucleobranchiate MoUusks. By Mr. Lovell Reeve, 

 A.L.S. 



[With a Plate.] 

 To the Editors of the Annals of Natural History. 

 Gentlemen, 

 In the course of a recent journey through Holland^ I was for- 

 tunate enough to become the purchaser of a valuable collec- 

 tion of shells that had been formed with considerable taste by 

 the late Dutch Governor, General Ryder, stationed at the Mo- 

 luccas. Amongst several of extreme rarity and beauty was a 

 fine glassy Nautilus, which I at first took to be the celebrated 

 Carinaria vitrea of the Paris Museum*, and of which a model 

 in wax has been exhibited in the British Museum for many 

 vears. But.it was destined to be yet more precious, for on 

 referring^o Lamarck's description of that species, as well as to 

 the figure in Martini's ' Conchology,' I found it to be perfectly 

 distinct. As I am unable to identify this species with any of 

 those since described by Rang, D'Orbigny, or Benson, I for- 

 ward you the following specific characters, accompanied with 

 drawings on copper, for publication in the ' Annals.' 



On account of the elegant slender form which characterizes 

 this shell, I propose to call it the 



Carinaria gracilis. Car. testa hyalina, iridescenti, gracili, late- 

 ribus elongato-compressa, transversim rugosa, rugis ad carinam 

 dorsalem obliqu^ terminantibus ; carina recta, sublata, margine 

 simplici, integro ; vertice minimo, compresso, ad dextram involute ; 

 aperturd oblongo-ovata, versus carinam angustiori. 



Long. Sy^^ ; lat. 1^ ; alt. 2 poll. 



Hab. ? Mus. Stainforth. 



The Carinaria gracilis differs materially from the Carinaria 

 vitrea : first, in general form, being higher and much more 

 slender and compressed at the sides ; the keel, extending from 

 the vertex to the margin of the aperture, is accordingly of 

 greater length ; secondly, in the vertex being still more mi- 

 nute, more compressed, and more closely rolled inwards ; and 

 thirdly, the most marked difference, in the width and simple 

 straight edge of the keel, which in the Carinaria vitrea is den- 

 tated. 



I am unable to give the true habitat of this species, though, 



* Mr. Gray appears to have fallen into the same error as myself; for in 

 his zeal to communicate the circumstance of my having brought this very 

 rare shell to England, he notices it in this work, vol. vi. p. 239, as the Cari' 

 naria vitrea, Lamarck. 



