Occasional Papers of the Museum of Zoology ■ 1\ 



Distribution: Jamaica, Haiti, St. Thomas, St. Vincent, 

 Grenada. Curacao : Sint Marie Spring (Ccl3). Aruha : reser- 

 voir and brook at Fontein ( Ac2) . Bonaire : well in Kralendijk 

 (not collected), and Pos Baca (Bel). Klein-Bonaire: Pos di 

 Cas (Kcl). 



Guilding's figures 1 and 2 show both the shell and the 

 animal; figure 3 is apparently a young specimen. They all 

 represent the smooth form, but show evident, spiral striations. 

 From authentic specimens in the A. N. S. P. (no. 67466, from 

 C. B. Adams), P. jamaicensis appeare to be a s^Tiom-m. This 

 species is more slender and slightly smaller than P. coronatus 

 (Pfr.) ; parvula is, of course, the older name. Although the 

 original figure looks very much like parvulus, Paludestrina 

 valenciae Preston (1909; Ann. Mag. Nat. Hist., Ill, p. 513, 

 fig. 16), from Lake Valencia, Venezuela, is still smaller and 

 more slender; its last whorl is shorter in proportion to the 

 spire, and the aperture is more nearly circular (A. N. S. P., 

 no. 99401, three cotypes). 



All of my specimens are dull greenish in color. Those from 

 Curasao, Aruba and Bonaire belong to the typical, smooth 

 form (figs, xi-45, 46), but the lot from Klein-Bonaire contains 

 a small proportion of weaklj- spinose shells (fig. xi-47). How- 

 ever, none is as markedly angulate as P. coronaia, and the 

 black-margined thread-carina is simply crenulated into low, 

 triangular cusps. In my specimens, this carina begins as a 

 slightly raised line on the penultimate whorl, gradually de- 

 velops into the crown of spines, and then dies out again 

 towards the aperture. 



Measurements 



alt. maj. diam. alt. apert. diam. apert. wiiorls 



Figure 45 4.62 54(2.49) 37(1.73) 78(1.35) 6 



Figure 46 4.48 49(2.19) 36(1.63) 76(1.25) 6^4 



Figure 47 3.60 58(2.10) 41(1.47) 77(1.13) 5^ 



PLANORBIDAE 



Planorhis paUidus C. B. Adams 



Planorhis pallidum C. B. Adams (1846; Proe. Boston Soc, II, 102). P. 

 paUidus Clessin (1884; Chemn., II, p. 122, fig. xi-7). P. circumlincatus 



