142 



with the exception of the one now under notice, we find that that 

 finger has only three bony phalanges*. There are, however, several 

 characters present which appear to belong exclusively to the present 

 genus, such as the form of the snout and nostrils, the singular mark- 

 ings on some of the membranes, and the peculiar quality of the fur. 



EXPLANATION OF PLATE LIV. 



Fig. 1. Mystacina tuberculata, three-fourths of the natural size. 

 a. Head of the same, of the natural size. 

 b & c. Cranium of the same, of the natural size. 

 d. Magnified representation of the front teeth of the same. 

 Fig. 2. Magnified representation of the front teeth of Nyctinomus dilatatus, show- 

 ing the resemblance between them and the same parts in Mystacina 

 tuberculata. 



3. On the Jamaican Cyclotus, and the Description of 

 Twenty-one proposed New Species and Eight New 

 Varieties of that Subgenus from Jamaica By the 

 Hon. Edward Chitty. 



Before entering upon the task of description, it seems advisable to 

 offer a few observations upon the difficulty which has hitherto sur- 

 rounded this group of Cyclostomidce inhabiting Jamaica. 



The late Professor C. B. Adams, in Contr. to Conch., No. 8, p. 

 140, et seq. wrote an article upon it; and although the required 

 study enabled him to add seven new species to the former Jamaican 

 list, a perusal of his paper will show that he laboured under great 

 doubts and without clear satisfaction as to the result. The fact is, 

 that almost all the species in the Jam. Cat. of Adamsf, 1851, from 

 No. 68 (for C. Duffianus, No. 67, is not a Jamaican, but a South 

 American species — -fide Adams and Mr. Bland, who found duplicates 

 in South America), to No. 77 inclusive, run so much into one another 

 in outward form of the mere shells, wanting the opercula, that it is 

 next to impossible to classify them. There is also the difficulty of 

 young and old shells intermingled, which, as regards some of the 

 species, renders the " confusion worse confounded," particularly in 

 the young of C. Jamaicensis, and the more mature of C. crassus. 



The group in question, and many others, lead me to the firm con- 

 viction that, unless the differences are very marked, a single specimen 



* A similar peculiarity occurs in the genus Centurio, which, when first de- 

 scribed by Dr. Gray, was thought to be a native of the Old World, but there was 

 some doubt as to the exact locality from which it had been received. But other 

 examples have been since obtained from the New World, and its near alliance 

 with the tailless Phyllostomidae satisfactorily established. The existence there- 

 fore of four phalanges in this finger in Centurio cannot be considered, as in 

 Mystacina, as an exception to a general rule, but on the contrary as a further 

 extension of it. 



f Whenever the name " Adams" is mentioned in these communications, the late 

 Professor C. B. Adams, of Amherst College, America, is referred to, unless other- 

 wise specified. 



