170 BULLETIJN 181, UlslTEO STATES NlATTONAiL MUSEUM 



openly umbilicated, and marked by the incremental lines, which grow 

 even stronger on the nmbilical wall, which also shows some spiral 

 lirations. Aperture circular, pale brown within ; peristome expanded 

 and reflected, forming an auricle at the posterior angle ; the expanded 

 portion is marked by concentric lines of growth, which give the im- 

 pression of a double peristome. The notch on the parietal wall is 

 rather shallow and openly U-shaped. 



The type, U.S.N.M. No. 128285, was collected in damp woods at 

 Motzorongo, Veracruz, Mexico. It has lost the extreme nuclear tip; 

 the 4 whorls remaining measure : Height, 18.6 mm. ; greater diameter, 

 32.8 mm.; lesser diameter, 23.8 mm. 



The huge size and heavily thickened peristome readily distinguish 

 this from the other Cyrototomas having a spiral thread below the 

 suture. 



CYRTOTOMA SALLEANUM (v. Martens) 



Plate 22, Figukes 19-21 



1865. Cyclophorus salleanus v. Mabtej^s, Malak. Blatter, vol. 12, p. 151. 



1880. Eahropoma salleanum Fischer and Cbosse, Mission scientifique au Mexique 

 et dans I'Amerique Centrale, vol. 2, pt. 7, pi. 35, fig. 4. 



1886. Eahropoma (Cyrtotoma) salleanum Fischh:e and Crosse, ibid., pp. 128, 

 133, pi. 38, fig. 1. 



1890. Cyclophorus (Cyrototoma) saHeontts von Martens, Biologia Centrali- Ameri- 

 cana, p. 7. 



1897. Cyrtotoma salleanum, Kobelt and Mollendoeff, Nachrb. deutschen malak. 

 Ges., vol. 29, p. 140. 



1922. Cyrtotoma mexicanum salleanum H. B. Baker, Occ. Pap. Mus. Zool. Univ. 

 Michigan, No. 106, p. 42, pi. 16, figs. 8-12. 



1928. Aperostoma mexicanum salleanum H. B. Baker, Occ. Pap. Mus. Zool. Univ. 

 Michigan, No. 193, p. 51. 



Shell rather large, depressed-helicoid, covered by a dark straw-col- 

 ored periostracum. The extreme nuclear tip has a pale orange tint; 

 the interior of the aperture is bluish white. Nuclear whorls about 2.5, 

 smooth. Post-nuclear whorls well rounded, marked by slender, hair- 

 like, retractively slanting, closely placed axial riblets. There is a feeble 

 spiral cord at the summit. Suture narrowly channeled. Periphery 

 well rounded. Base somewhat inflated, well rounded, and marked by 

 the continuation of the axial riblets, which here are a little stronger 

 than on the spire and still stronger than on the umbilical wall. The 

 umbilicus is open and moderately broad. Aperture almost circular; 

 peristome expanded and reflected, forming an auricle at the posterior 

 angle. The notch on the parietal wall is U-shaped and rather deep. 



The specimen described and figured, U.S.N.M. No. 211098, is one of 

 two collected by C. R. Orcutt at Cordova, Veracruz, Mexico. It has 6 

 whorls and measures : Height, 18.7 mm. ; greater diameter, 31.3 mm. ; 

 lesser diameter, 22 mm. 



