British Association, 1839 



10. Cardiad^e. Mantle open, fimbriated. Foot hamate and digitiform. Siphons 

 very short, united nearly to their ends. Apertures, one plain and one fimbriated. 

 Cardium. 



11. Chamad^e. Mantle closed, except a small aperture for the foot, and two fim- 

 briated siphonal openings. Foot hamate. Isocardia. 



12. Lucinad^e. Mantle united in great part, leaving an opening anteally for 

 the foot, which is slender and digitiform. Siphons very unequal, one being often 

 nearly obsolete; both apertures plain. Lucina, Cyclas (?) 



13. KelliadjE. Mantle closed, except a small aperture for the foot, and two 

 nearly sessile plain siphonal openings. Kellia, Galeomma, Lepton (?) 



14. Unionid^e. Mantle open. Siphons very short, fimbriated ; sometimes one 

 obsolete. Foot very large. Unio, Anodon. 



15. Dreissenad^;. Mantle in great part closed. Siphons very short, fimbriated, 

 and foot digitiform. Dreissena. 



16. MytilidjE. Mantle open, and not closed, or only partly closed to form 

 siphons. Foot very small, Mytilus ; and in an allied group, Pinna and Avicula. 



17. Arcade. Mantle open. Siphons very short, or considerably developed and 

 then united. Foot disciform. Area, Pectunculus, Leda, Nucula. 



Section B.— MONOMYAKIA. 



18. Pectenid^e. Mantle completely open, fimbriated and eyed. Foot well 

 developed. Pecten, Lima. 



19. Ostread^e. Mantle freely open. Foot obsolete. Ostrea, Anomia. 



A discussion followed the reading of this paper, in which the Prince of Canino, 

 Mr. Lovell Reeve, Dr. Carpenter, and Prof. Milne-Edwards, took part. The 

 principal points alluded to by the speakers were the position of particular genera of 

 shells in the arrangement of Prof. Forbes. 



' On the Anatomy of Scyllaea,' by A. Hancock and D. Embleton, M.D.— The in- 

 ternal structure of this animal was found pretty accurately to agree with the details 

 given by Cuvier, though some important matters relative to the digestive apparatus 

 seem to have been overlooked. The presence of a gland at the commencement of the 

 oesophagus, its small stomach receiving large ducts from the biliary masses, its large 

 and long intestine, approximate it to the Dorididae ; but the stomach with an internal 

 dental apparatus would appear to be peculiar. Its branched system of tubes in the 

 skin and branchial tufts show its relation to the Eolididae, but the re-division of some 

 of these tubes in the periphery of the globular biliary organs, with the convolutions of 

 which they communicate on the one hand, and the passage of others on the other hand 

 into the intestinal canal, are peculiarities of structure not found in either of the families 

 mentioned. 



* Notes on British Mollusca, with Descriptions of New Species,' by J. Alder and 

 A.Hancock. — The species described have been discovered since the last meeting. 

 They are Proctonotus (?) splendidus, remarkable for bearing a crest between the dorsal 

 tentacles by which they are united together at the base. It is from Torbay and Fowey. 

 2. Scyllaea pelagica, taken at Falmouth by Mr. Cocks. 3. Tritonia lineata, from 

 Scarborough. 4. Eolis Peachii, dredged by Mr. Peach in Fowey Harbour. 5. Eolis 

 exigua, or Laminaria, at Fowey and Falmouth, possibly the Tergipes lacinulatus of 

 Loven. 6. Chalidis nigricans, at Falmouth ; with 7. Acteonia corrugata, and 8. the 



