230 Mr C. Collier on Univalves. 



the species of Cyprtea, in Btdla Ficus, B. Ovum, B. ampulla, 

 and some species of Buccinum, Stromhus, and Murex *. In most 

 species of Conus, and in Buccinum Cassis and Vihex, the walls 

 are peculiarly strong, with corrugated, internal, longitudinal 

 fibres. In some species of Murex, (as Tulipa, longicauda, ra- 

 mosa, and saxatilis), this tube is so narrow and delicate through- 

 out, that, considered in relation to the bulk of the animal, it is 

 worthy of physiological notice. 



The hmg-f forms the roof of the pulmonary cavity, and is 

 extended along the inferior surface of the mantle, with the heart 

 at its lower surface, or contiguous to the liver, and the intestine 

 parallel with its base. It is a single membrane, with the pulmo- 

 nary vessel along its summit, whose ramifications, being arranged 

 horizontally, like the teeth of a comb, constitute the fifth order, 

 Pectinibranches, of Cuvier's System. This organization belongs 

 to all the families, excepting Haliotis, Patella, and the Tubi- 

 cines. These differ by an approximation, in the character of 

 those parts, to bivalves ; and these by the colour of the circulat- 

 ing fluid. 



The liver is generally of a dark green aspect. In the genus 

 Conus it is brown, or reddish-yellow. The stomach lies com- 

 monly on its outer surface, but is sometimes, as in Strombus, 

 Haliotis, and Patella, imbedded within its substance. 



There is an organ, the crystalline stiletto |, confined, erro- 



• One species (Aluco ?) has the crop of a beautiful red colour, variegated 

 by the ramifications of the nerves. 



f 111 most individuals, there is a small additional membrane, of a dark 

 colour, placed above the larger, and towards the fringe of the mantle, which 

 receives a branch from the pulmonary vessel. As connected with this organ, 

 it may be observed that mollusca do not support want of water, and removal 

 from their habitats alike. The species of Volula and Buccinum generally (par- 

 ticularly B. oliva and B. harpa), die in a few hours ; those of Strombus and 

 Murex survive thirty -six, forty-eight, and even sixty hours ; Trochus niloticus 

 and lurritus live yet longer ; and Strombus pcdustris will live several days. 

 Excepting Trochus turritus and Strombus palustois, none have lived many days 

 in water, though changed once in twenty-four hours ; and those individuals 

 which die so soon in the air, scarcely ever live beyond the second day, re- 

 moved from their usual habitat. 



X Dans d'autres, il y a un veritable second estoniac separe, une espece de 

 coecum pres du pylore. Ce que ce canal a de plus singulier, et meme d'abso- 

 lument propre i certains acephales, e'est uile partie remarquee depuis long 



