42 
colouring as the Dasyurus Maugei, the black variety of which has 
received the name viverrinus. 
The following “‘ Monograph of Crassatella, a genus of Acephalous 
Mollusks (Family Mactracea),”’ by Mr. Lovell Reeve, was next read. 
The genus Crassatella was instituted by Lamarck for the purpose 
of associating certain bivalve mollusks that had been hitherto dis- 
tributed amongst the Mactre and the Veneres. Their shells exhibit an 
interesting peculiarity of character, differing 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 
Amphidesmata, and was therefore susceptible of farther division. 
With the view of uniting the intermediate species of these genera, a 
new genus was proposed by Deshayes, under the title of Mesodesma, 
and J have found great convenience in adopting it in my ‘ Systematic 
Conchology.’ Thus out of eleven species described by Lamarck as 
Crassatella, six only can be allowed toremain. 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, 
distinguishing the new ones by the addition of the specific charac- 
ters. 
1. CrassaTELLa CASTANEA. Crass. testd ovato-trigond, gibbosd, 
umbonibus plané erosis, epidermide castaned, quasi politd nitente, 
indutd ; intis subfuscd ; latere antico rotundato ; postico angulifero, 
abrupto. Reeve, Conch. Icon.* Crassatella, pl. 1. f. 3. 
Long. 34; alt. 3 poll. Mus. Stainforth, Saul, Walton. 
Hab. ad oras Nove Hollandiz. 
The Crassatella castanea is the largest and perhaps the best defined 
species of the genus; its shell is covered with a shining horny epi- 
dermis, and both valves are singularly eroded at the umbones. I 
know of three specimens of this fine shell, and each of them fully 
exhibit this last-mentioned peculiarity. 
2. CrassaTELLA Kinecicoza. Lamarck, Anim. sans vert., vol. v. 
p. 481; Reeve, Conch. Icon. Crassatella, pl. 1. f. 5. 
Hab. ad oras Nove Hollandiz. Mus. Stainforth. 
A specimen of this species, in the possession of the Rev. Mr. 
Stainforth, is the only one that I have seen. 
8. CRASSATELLA DECIPIENS. Crass. testd ovatd, subgibbd, epider- 
mide fusca indutd, vividé radiatd, radtis ab umbonibus ad margines 
* Having made accurate drawings of the Crassatelle, 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 
«‘ Concnotoeia Icontca.” 
