Notes on certain Terrestrial Mollusks. 151 



0. tenella C. B. Ad., is the same, and also, I imagine, in the 

 other Jamaica allied species, although the fact is not discoverable 

 on examination of their apertures. 



The structure of C. Agnesiana C. B. Ad., is shown in PI. v. 

 fig. 16. In other species the axis has revolving lamelloe, — there 

 are two in C. pruinosa Mor. (PI. v. fig. 17), and from three to 

 six in 0. Oviedoiana Orb., within each of the whorls, — the num- 

 ber increasing towards the base of the shell. 



I directed the attention of Poey to the formation of C. elatior, 

 and he sent me a specimen marked C. Oviedoiana, and opened 

 so as to exhibit the extraordinarily developed lamella shown in 

 PI. v. fig. 18. I have since detected the same in two other 

 specimens ; in one it is on the outer side of the axis in the 

 second whorl, and in the other, it extends from the third to the 

 second whorl, counting upwards from the base. 



On subsequent more careful examination, Poey found the 

 axis of C. Oviedoiana as I have above stated, and that the shell 

 forwarded to me, of which he had other specimens, is of a 

 different species, — the large lamella figured being constant, as 

 well as other characters sufficiently distinguishing it. He 

 has described it as 0. strangulata. 



Observations on the internal structure of shells are not 

 ^evoid of scientific value, aiding in the determination of the 

 genus, as in the case of Proserpina opalina, and of the species 

 in that of Oylindrella strangidata. 



IV.— Corrections and Additional Facts, especially as 

 to the Habitat of Sundry Species. 



Helix Cassiquiensis Newcomb, M. S. 



Pfeiffer and Eeeve erroneously attribute this species to 

 Cuba. Dr. Newcomb assures me that he collected it near 

 the Cassiquia Creek, in Demerara, from whence its specific 

 name. 



