428 Rev. M. J. Berkeley on Valuta denticuluta. 



I was surprised to find manifest indications that both were pulmonife- 

 rous, which were confirmed on a minute inspection of the internal 

 structure, as far as perhaps could be expected in such small animals, I 

 was enabled in the former to trace distinctly the course of the vessels, and 

 was decidedly of opinion that the lungs were constructed for the breath- 

 ing of air unmixed with water. In the other case I was not so successful, 

 though the utmost pains were taken : but as the animal is only half the 

 size the difficulty was much increased. I am enabled however to assert 

 that I could detect nothing; like branchiae; and, what is more to the 

 point, that the vault of the cavity of respiration was traversed by a mul- 

 titude of minute vessels all tending one way towards a large vessel running 

 down in the direction of the heart; which is exactly the structure in 

 pubnoniferous Molhisca. This perhaps will be esteemed as decisive 

 when the external characters of the animal are taken into consideration. 



VOLUTA DENTICULATA, Mont. 



Foot obovate-oblong, pale ochraceous with shades of cinereous, obtuse 

 in front, more or less obtuse behind, not evidently composed of two 

 laminae. 



Tentacula highly contractile, filifoim, obtuse, cinereous, slightly 

 annulated, darker at the tip ; eyes at the internal base. 



Muzzle porrected, not truly proboscidiform, lip large, notched in 

 front as in Limnaa, cinereous: the central poition faintly annulated; 

 on each side near the margin there is a round raised spot. Mouth fur- 

 nished with a small tooth above. 



Mantle closed all round, with the exception of a perforation at the 

 point of juncture of the outer lip and spire for the admission of air. 



Fceces cylindrical (as in Limncea ) . 



Operculum none. 



If the mantle be carefully opened, and the vault of the cavity of 

 respiration examined with a lens under water, the pulmonary veins are 

 seen very distinctly running from all sides into one large vein, which runs 

 close to the sac of viscosity and carries the blood directly into the heart. 

 The sac of viscosity is very large, and without minute inspection might 

 be taken for branchi:ju : a comparison with that organ in Li/rnnceidce veri- 



