ODONTOSTOMUS. 71 



always more swollen. Length 35, diam. 12 mill. This form he 

 found in the country inhabited by the Guarayos, in the heart of the 

 humid forests of the northern frontier of the province of Chiquitos 

 (now prov. Santa Cruz), Bolivia, and in the province of Corrientes, 

 Argentina, in a wood near the Santa Lucia river, at a place called 

 Pasto reito. 



Paravicini reports this variety from the Rio Apa (Risso colony), 

 Argentina, collected by Dr. Borelli. 



I suppose d'Orbigny's figure of a living specimen to be drawn from 

 this variety. 



Perhaps the form collected by Bohls at Barranca de la Novia, 

 Paraguay, and referred by von Martens to var. " (b) paraguayanus 

 Ancey," is referable rather to major Orb. It is described as '" some- 

 what shorter (than var. liohhi} and comparatively wider, 41-4 1 ^ 

 mill, long, 11^-12^ wide, with 12 to 12^ whorls; corresponding 

 pretty well with 0. icagneri var. paraguayana Ancey." 'Two 

 specimens out of 6 have a suprapalatal fold. It differs from Ancey's 

 variety in the presence of a lower palatal fold in all the specimens 

 examined, while the absence of this fold is the chief distinguishing 

 character of the Corumba race. The mere dimensions of Corumba, 

 parayuayanus are inconstant, one of the specimens before me having 

 exactly the measurement of Orbigny's var. major. 



Var. MINOK Orbigny. PI. 12, figs. 04, 05. 



D'Orbigny's other variety, minor, is smaller, much elongated, 

 strongly striate, a/ways hasjire teeth of which three are on the outer 

 lip. Length 30, diam. 7 mill. This variety lie found between 

 Santo Coni/.on and San Juan, in the province of Chiquitos (now in 

 the southeastern part of prov. Santa Cruz), Bolivia, on wooded 

 ridges. Subsequent collectors do not seem to have encountered this 

 form, which seems to differ from true spixii not only in having an 

 additional fold (the suprapalatal), but also in being narrower. 



The figures given by Deshayes apparently represent this variety. 

 I have copied them on pi. 12, f. 04, 05. 



Var. PARAGUAYAN-US (Ancey). PI. 12, fig. 07 ; pi. 15, fig. 34. 



Larger and especially wider than spixii, the striation very distinct 

 on the median whorls, fainter above and below ; brown and white 

 color pattern distinct ; whorls 11-lH. Aperture, with three teeth, the 



