42 University of Michigan 



which were placed in Tudora s. s. by Henderson and Bartsch 

 (1920, p. 77) . However, the peristome of these species appears 

 to be more like that of Colobostylus, and it seems probable that 

 they will be found to be more closely related to some of the 

 other groups of the Greater Antilles. In this connection, 

 attention is called to the fact that Licina "Browne" Gray 

 (1847; P. Z. S., XV, 81), monotype "Turbo labea," is three 

 years prior to Tudora Gray (1850). In the present paper, 

 the genus Tudora is considered to include only the species 

 listed below under the three minor groups, Bonairea, Tudorata 

 and Tudora s. s. Regardless of the question of generic inclusion, 

 these three groups are certainly quite distinct from any of the 

 other groups of American Pomatiasidae, although Tudorata 

 possesses certain characters in common with a mainland group, 

 which includes AdamsieUa aripensis Guppy, from Trinidad, 

 Cyclostoma aspratilis Morelet, from Ecuador, Cyclcstoma 

 rigidula Morelet, from Guatemala, and my "Tudora" william- 

 soni, from Venezuela. 



Subgenus Bonairea, new 

 This subgenus is characterized by the small size, the solute 

 last whorl, the simple, continuous, unreflected peristome, the 

 convex operculum (quite similar to Ramsdenia) , and the stout, 

 aculeate cusps of the outer lateral tooth of the radula. The 

 chondroid plate of the operculum is smaller than the interior 

 of the aperture, but the calcareous plate is larger; the entire 

 structure fits the peristome like a flanged cover and the animal 

 is usually unable to draw it inside. In all of the other species 

 of Tudora, as in most of the Chondropominae, the operculum 

 is readily withdrawn into the aperture. The radula of 

 Bonairea is quite different from that of Ramsdenia, which is 

 closely related to other Greater Antillean groups ( Annularella, 

 Rolleia, and Blaesospira). Monotype: Tudora maculata. 



Tudora maculata "Bland" H. Burrington Baker 

 (1924; Naut. XXXVII, 92) 

 Type locality: (B3a) base of east-facing escarpment, about 

 1/2 kilometer south of Kibra di Montague, Bonaire. 



