302 Zoological Society. 



ence. Several of them were exhibited at a meeting of the Literary 

 Society of Madras some time ago, and were much admired for their 

 beauty and accuracy. 



The subjects for the present publication will be selected so as to 

 present an agreeable variety, and most of them will be figured here 

 for the first time. 



The drawings will be lithographed both on quarto and royal octavo 

 paper. The colouring will be finished under the author's own super- 

 intendence. 



The letter-press will contain a full description of the species figured. 



The work is proposed to be published by subscription. Subscri- 

 bers' names received by Mr. Lizars, Engraver, Edinburgh. 



We have, at the same time, received a specimen of one of the il- 

 lustrations, which is well executed and carefully coloured. 



PROCEEDINGS OF LEARNED SOCIETIES. 



ZOOLOGICAL SOCIETY. 



Feb. 22, 1842. — William Horton Lloyd, Esq., in the Chair. 



The following " Monograph of Crassatella, a genus of Acephalous 

 Mollusks (Family Mactracea)," by Mr. Lovell Reeve, was read. 



The genus Crassatella was instituted by Lamarck for the purpose 

 of associating certain bivalve luollusks that had been hitherto dis- 

 tributed amongst the Mactra and the Ve?ieres. Their shells exhibit an 

 interesting peculiarity of character, diflfering from the former in being 

 thick and solid, and for the most part covered with a strong brown 

 epidermis ; and from the latter in the position of the ligament. The 

 genus, however, as introduced by Lamarck, was yet imperfect ; it 

 included five species that could not easily be distinguished from his 

 Ainphidesmata, and was therefore susceptible of farther division. 

 With the vieM' of uniting the intermediate species of these genera, a 

 new genus was proposed by Deshayes, under the title of Mesodesma, 

 and I have found great convenience in adoi:)ting it in my ' Systematic 

 Conchology.' Thus out of eleven species described by Lamarck as 

 CrassatellcB, six only can be allowed to remain. Since his time, how- 

 ever, several new and important species have been discovered ; two 

 have been described by Sowerby in the ' Proceedings' of this Society, 

 one by the same author in his ' Appendix to the Tankerville Cata- 

 logue,' and I have now the pleasure of exhibiting ten more, which 

 I believe to be entirely new to science. 



To make this a complete monograph, I mention all the species, di- 

 stinguishing the new ones by the addition of the specific characters. 



1. Crassatella castanea. Crass, testa ovato-trigond, gibbosd, 

 umbonihus plane erosis, epidermide castaned, quasi politd nitente, 

 indutd ; intus sub/used; latere antico rotundato ; postico angulifero, 

 abrupto. Reeve, Conch. Icon.* Crassatella, pi. 1. f. 3. 



* Having made accurate drawings of the Crassatella', with a view to 

 publication at some future period, I venture to refer to a pictorial and de- 

 scriptive repertory of species now in course of preparation, to be entitled 



" CONCHOLOGIA IcONICA." 



