57 



July 8, 1834.. 



William Yarrell, Esq., in the Chair. 



A Letter was read addressed to the Secretary by M. Julien 

 Desjardins, Corr. Memb. Z.S., dated Mauritius, January 10, 1834. 

 It accompanied a collection of objects of Zoology, consisting chiefly 

 of Mammalia and Birds, which were exhibited to the Meeting. 



Mr. Gray exhibited various undescribed Shells, chiefly contained 

 in his own collection. He characterized them as follows : 



Unio Nov^ Hollandi^. Un.testd ohlongo-elongntd, gracili, 

 solida ; antice subcompressci, Icevi, rotundatu, postice subventri' 

 cosd, productd, tuberculis magnis incequalibus in seriebus curvatis 

 radiantibus dispositis ; disco argenteo purpurea maculato, margine 

 injeriore antice crassissimd ; dente cardinali anteriore parvo, 

 parum elevato, bituberculato ; dentibus posterioribus parvis, sub 

 cartilaginis margine posteriore positis ; periostraca crassu, nigra. 

 Hab. in Novae Hoilandiae flumine Macquarrie, 70 circiter mill, 

 ab ejus ostio. 



Anodon Parishii. An. testa ovatd, ventricosd, solidd ; antice 

 compressd, subproducta, subgracili, postice expansd, dilatatd, 

 rotundatd ; margine cardinali rectd, marginis injerioris dimi' 

 dium longitudine cequante ; disco margaritaceo-albo ; periostraca 

 brunneo-nigrescente. 

 Long. 74-, alt. 3f poll. 

 Hab. in fluviis Paraguayae. 



The submarginal scar has an acute inflection under the hinder 

 muscular one; and there are several small unequal scars behind 

 that of the anterior adductor^ as well as others, also unequal, under 

 the umbones. 



Anodon penicillatus. An. testd ovata, ventricosa, crassd, 

 solidiusculd, Icevi; antice subcompressd, rotundatd, subgracili, 

 postice oblique truncatd; ad marginem inferiorem postice di' 

 latato- rotundatd; disco albo, lineis angidaribus brunneo-ni- 

 grescentibus prope cicatricem muscularem submarginalem notato; 

 periostraca olivacea, Icevi. 

 Hab. in fluviis Paraguayae. 



The black lines of the inside of the shell are deposited along the 

 upper edge of the submarginal muscular scar, and are gradually co- 

 vered by the pearly layer deposited by the surface of the mantle 

 over the scar ; the interior ones, being the most thickly covered, 

 are the lightest in colour. 



No. XIX. — Proceedings of the Zoological Societv. 



