lo Unizrrsity of Michi'nv 



Bitliniidus coriacciis, var. b. One shell from the grass on 

 the savannah (H, iv) is very large and slender. It is buff in 

 color and lacks the sutural band. If obtained in larger num- 

 bers, it would seem to be worthy of at least subspecific recog- 

 nition. It measures : 

 Altitude Greatest diameter Height aperture Diameter aperture 



21.7mm. 47(10.1 mm.) 41 (8.8 mm.) 30 (6.4mm.) 



DryuKriis dominicus (Reeve) (1850). Nine adults and 5 

 smaller specimens; from leaves of trees in the lowland jungles 

 (H, i, b), in savannah forests (H, iii, b) and dead shells from 

 ground in latter (H, iii, a) ; also one immature specimen from 

 near Lake Catemaco, and numerous juveniles along Arroyo 

 Hueyapam (H, ii, a). These shells are very variable in col- 

 oration ; one young specimen has all of the 5 bands present, 

 but the upper 2 are broken into dots ; another has the upper- 

 most and lowest absent; two shells have bands 2, 3, 4 and 5, 

 with 2 and 3 broken ; while the remainder have only 3, 4 and 5, 

 with 3 and sometimes 4 broken. An example measures : Alti- 

 tude, 19 mm.; greater diameter, 55 (10.5 mm.). 



The jaw and radula were obtained from two dried speci- 

 mens. The radular formula (Figure 2) is 121 — i — 121. In 

 one radula the rhachidian tooth bears two cusps and is quite 

 symmetrical, but in the other its symmetry is usually disturbed 

 ])y the presence of a third, smaller cusp. In all cases, the basal 

 jjortion is long and slender. The remainder of the teeth can- 

 not be sharply divided into laterals and marginals. Most of 

 them have 4 cusps, but some of the inner three may have only 

 3 ; teeth of both types occur in a single longitudinal row. In 

 the outer portion of the radula the second cusp from the inside 

 is larger and more spatulate than the others. The base of all 

 of these lateral teeth is trapezoidal, and the posterior edge is 

 almost as broad as the anterior. The cusp-bearing portion 



