Linnean Transactions. 565 



dinalibus saoguineis antice coalescentibus, 7nans pedibus 2 

 anticis scabris, digitis purpureis ; posticis 8 antice spinosis. 



And the possession of both sexes furnishes the following cor- 

 rection of the generic character as given by Dr. Leach, 

 *' Cauda maris 6-articulata : femince 5-articulata, articulo ultimo 

 fere magnitudine corporis (quod mirum,) reliquls minutis." 



Scyliarus carinatus, another new species, is characterized as 



S, rufescente-vitreus, lateribus obscure crenatis, testa caudaque 

 carinatis. 



An amended character is also given for S. aequinoctialis, Fabr. 

 Supp. 



The paper concludes with a new species of Ibacus, 



I. ciliatus. I. nigro-flavescens, purpureo varius, corpore verrucoso : 

 verrucis ciliatis, testa utrinque ante fissuram 2-deutata, postice 

 6-deDtata : 



and the ascertaining the locality of Atya scabra, Leach, which 

 occurs in incredible numbers in the mountain streams of St. 

 Vincent's, where it is caught by the negroes in baskets for the 

 market. 



In the " Observations on some of the Terrestrial Mollusca of 

 the West Indies;" from the same pen, we are preseated with 

 characters of the animals that form several shells common in col- 

 lections, but the inhabitants of which have remained hitherto 

 undescribed. This laudable direction of his studies to the inha- 

 bitants rather than to their habitations, will enable the writer to 

 add much and valuable information to that already possessed on 

 this subject, (the importance of which is becoming daily more ex- 

 tensively acknowledged) ; and in other cases doubtless, as iu one 

 instance in the present paper, to refer to their proper genera, shells 

 which from ignorance on this point had been previously wrongly 

 located. We allude to the Carychium undulatum, Leach, the 

 Auricula Caprclla, Lam. to neither of which genera is the animal 

 referable, as both of these possess only two tentacula, while the 

 inhabitant of the shell in question oflVrs four, ft has, therefore, 

 been necessary to establish a new genus to receive it, which has 



