110 Historical Sketch of Improvements in [Aug. 



Hemiloma, whose shell is ovate, elevated, and smooth. 

 Aperture, obhquely-elliptic, with the interior peritreme elevated, 

 and a little twisted. Unibihcus very small. 



The last number of the Journal de Physique contains a con- 

 cordance of the land and freshwater moUusca of Great Britain, 

 arranged systematically by Baron de Ferrussac. 



De France has established as a distinct genus the Capulus 

 Cornucopia of Lamarck, which he denominates Hippomx, from 

 the form of its muscular impression, and describes four species, 

 all of which are fossil. — (Bull, des Sciences, 1819, p. 9.) 



Say, with his usual zeal, has given some papers on this class 

 to the Academy of Philadelphia, and has discovered some new 

 o-enera. 1. Polygyra, of the family Helicid.e. 2, Oly- 

 GYRA, belonging probably to the family Auriculad.e. 



Class II, Cephalopoda. 



Lichtenstein has established a new genus of this class, under 

 the name Onychoteuthis, which resembles the genus 

 LoLiGO, in general aspect, but differs in having all the brachial 

 suckers armed with hooks. This genus probably includes Dr, 

 Leach's second division of Loligo (see Zool. Misc. iii. p. 141) ; 

 the third division of which now constitutes the genus An- 

 cisTnocHiRVS of Dr. Leach, characterized by having only the 

 suckers of the distal extremities of the supplementary arms 

 furnished with hooks, 



Blainville has written a very long and interesting dissertation 

 on the animals found in the shells of the genus Argon acta, 

 or Paper Nautilus, with a view to prove them to be mere para- 

 sites ; an opinion long entertained by Sir J. Banks and other 

 naturaUsts, but denied by Cuvier. A new species of this genus 

 is described by Mr. Say, in a letter to Dr. Leach, which is 

 inserted in the last volume of the Phil. Trans.; and Dr. Leach has 

 lately obtained a second species out of the Argonauta Argo. As 

 we are, therefore, now acquainted with five species of Ocvthoe 

 (or of the supposed parasite) ; and as but three species o{ Argo- 

 nauta are known, the question respecting the parasitical nature 

 of the Ocvthoe seems to be set at rest. — (See Phil. Trans. 1811, 



p. 107.) 



Class III, Acephala. 



Bojanus has given us an anatomical dissertation on the Ano- 

 DON CvGNEUS. — (Joum. de Phys. tom. Ixxxix. p. 108.) 



Alasmodonta* (Say, Joum. Acad. Phil. i. 469), a new 

 genus of the family L'Nionid.e, having its shell elongate ; its 

 hin£;e with a strong tooth in each valve. Situation between 

 Unio and Anodon (misnamed Anodonta). 



Dr. Leach's opinion as to the mode by which the acephalous 

 animals close their shells almost entirely, without muscular 

 action, by means of abductive elastic ligaments, is now 



• It should be Alasmodon, 



