THE 
ZOOLOGICAL JOURNAL. 
1832—1834. 
Art. LI. Remarks on the nature of the Respiratory Organs 
in certain littoral Mollusca of Madera. By the Rev. R. T. 
Lowe, 4. M. 
In reperusing, after a considerable interval, my paper in the 19th 
number of the Zoological Journal, (page 280,) in which I detailed a 
series of experiments, instituted with a view to ascertain something of 
the nature of the respiratory organs in Melampus, Pedipes, and Trun- 
catella ; it has struck me that I have been too hasty in regarding some of 
my conclusions as positively or finally established: or rather, perhaps, 
in not sufficiently explaining, or defining, the actual extent to which 
my resulting speculations might safely, and legitimately, be admitted. 
It is very certain, from the fact of these Mollusca surviving total im- 
mersion for so long a period as they did, in water, that a remarkable 
difference in their powers, in respect to an ability for enduring complete 
deprivation of atmospherick air, from those of our land Pulmonifera 
in general, may be safely considered as established,* Now from this 
* It is essential to remark that I do not consider this position invalidated by 
the following quotations from the observant Miiller, or others of a similar 
character, Speaking of his Helix pellucida (Vitrina, Drap.) he observes, 
“ Limacem in aqua perire affirmat Clariss. Geoffroi; hoe sese nobis, etiamsi 
* periculam in pluribus fecerimus, minus probavit; in aquam enim immissi, 
* fundum statim petierunt, ac totum corpus e testi protulerunt; tentacula 
Von. V. cc 
