HISPANIOLAN AND BAHAMAN ANNULARIIDAE 129 



SAI<L,f:POMA AMBIGUUM (Lamarck) 



Plate 19, Figure 4 



1822. Cyclosioma ambigua Lamarck, Histoire naturelle des animaux sans verte- 



bres, vol. 6, pt. 2, p. 145. 

 1841. Cyclostoma interruptum Delessert, Recueil de coquilles , . ., pi. 29, fig. 2. 



(Not C. interruptum Lamarck.) 

 1850. Choanopoma ambigua Gray, Nomenclature of molluscous animals and shells 



in the collection of the British Museum, pt. 1 : Cyclophoridae, p. 50, 



No. 9. 

 1852. Cistula? ambigua Pfeiffer, Monographia pneumonopomorum viventium, 



p. 271. 

 1862. Cyclostoma albescens Weinland, Malak. Blatter, vol. 9, p. 87. 

 1891. Tudora ambigua Crosse, Journ. Conchyl., vol. 39, p. 177. 

 1920. Chondropoma (Chondropomium) ambigua Henderson and Bartsch, Proc. 



U. S. Nat. Mus., vol. 58, p. 60. 



Shell elongate-ovate, yellovi^ish vv^hite, w^ith interrupted spiral bands of 

 brown, of v^^hich four are present between summit and periphery and 

 five on the base. These bands show the interior of the aperture but do 

 not ray the aperture. Nuclear whorls 2, inflated, strongly rounded, 

 microscopically granulose, forming a rather small apex. Postnuclear 

 whorls well rounded, narrowly shouldered at the summit, and marked 

 by strong, almost lamellar axial ribs, which become somewhat expanded 

 at the summit and render the suture decidedly crenulated. Of these ribs, 

 24 occur on the last whorl. In addition to these strong axial ribs, there 

 are occasional finer axial threads present. These, however, are not 

 regularly distributed but occur only occasionally and may appear singly 

 or several of them grouped in an intercostal space. Suture well con- 

 stricted. Periphery well rounded. Base moderately long, well rounded, 

 microscopically broadly openly umbilicated, and marked by the continua- 

 tion of the axial ribs which also extend on the umbilical wall. The um- 

 bilical wall has three moderately strong spiral cords that render the 

 axial ribs somewhat scalloped at their junction. Aperture oval; peri- 

 stome double, the outer broadly flaringly expanded, widest at the junction 

 of the inner and basal lip and narrowest at the parietal wall, decidedly 

 auriculated at the posterior angle and marked by concentric lamellae; 

 inner peristome exserted and slightly reflected. Operculum typically sal- 

 lepomid. 



The specimen figured (U.S.N.M. No. 504043), one of five, comes 

 from 5 miles west of Jeremie, Haiti. It has 4.5 whorls remaining and 

 measures: Height, 19.7 mm.; greater diameter, 12. i mm.; lesser di- 

 ameter, 9.3 mm. 



This species, of which we have a large series from many stations, 

 ranges from Jeremie west to Trou Bonbon. 



U.S.N.M. No. 504054 contains 55 specimens collected by Henderson 

 and Bartsch at Jeremie. 



