﻿72 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 102 



I wish to thank Albert Greenberg, of the Everglades Aquatic 

 Nurseries in Tampa, for his many kindnesses in connection with the 

 field work. 



SYSTEMATIC POSITION 



This paper is primarily a study of the anatomy and the life history 

 of the fresh-water snail Thiara granifera. Although much material 

 from all parts of the Pacific region has been critically examined, it 

 is felt that a detailed analysis and presentation of the various sub- 

 species and related species is a task at present beyond the scope of 

 this study. However, a brief systematic orientation is included here 

 for those wishing to use this anatomical study for comparative work : 



Phylum : MOLLUSOA 



Class: GASTROPODA 



Order: PROSOBRANCHIATA, Suborder TAENIOGLOSSA 



Family: THIARIDAE (=MELANIIDAB) 



Subfamily: THIARINAB 



Genus : Thiara Roding, 1798 



Subgenus : Tarebia H. and A. Adams, 1854 



Species : granifera Lamarck, 1816 



The genus Thiara Roding, 1798, more familiarly known in older 

 literature as Melania Lamarck, 1816, is represented by some fewer 

 than 100 named species and forms, all of which are from the warmer 

 regions of southern Asia, the East Indies, and the larger Pacific 

 islands. As more and more species were described subgeneric names 

 were proposed, such as Plotiopsis, Tarebia^ Melanoides^ and Tiaropsis, 

 and these were later raised to generic standing. Recently there has 

 been a tendency in the opposite direction, to recognize fewer species 

 and to include these subgenera under the single genus Thiara (Abbott, 

 1948). The subgenus Tarehia H. and A. Adams, 1854, contains such 

 species as granifera Lamarck, rudis Lea, and over two dozen names of 

 subspecific or doubtful varietal rank. The specimens that have been 

 used in this anatomical study came from Guam Island, in the Marianas, 

 and are most likely members of a widespread race of Thiara granifera, 

 which was given the name of mauiensis by Lea in 1856. 



GENERAL DESCRIPTION 



Thiara granifera is a relatively small gastropod, in which adults 

 may vary in shell length from 6.0 to 40.0 mm., although the commonest 

 size is approximately 25.0 mm. (one inch). The shell is rather 

 elongate with a straight-sided, pointed spire and is sculptured with 

 several spiral rows of beads or blunt tubercles. The aperture of the 

 shell is obliquely ovate, and the apertural lip is sharp. The color of 

 the shell and its thin periostracal covering is generally a light brown 

 to yellowish brown, which sometimes is flecked with small, dark, red- 



