THE NAUTILUS. 



VOL. XV. NOVEMBER, 19O1. No. 7. 



A NEW LAND OPERCULATE FROM HAITI. 



0. T. SIMPSON AND J. B. HENDERSON, JR. 



CERATODISCUS, nov. gen. 



Shell almost strictly discoidal ; spire very slightly raised ; whorls 

 few, nearly round, closely coiled except the last third of the outer 

 one, which leaves the penultimate whorl at a tangent and has a 

 groove on its inner side ; aperture nearly circular, scarcely thickened 

 or reflexed ; surface with finely reticulated sculpture ; epidermis cor- 

 neous. Operculum unknown. Probably one of the Cyclotidas. 



CERATODISCUS SOLUTDS, n. sp. PI. V, figs. 1, 2. 



Shell small, planorboid, the large nucleus slightly raised, but not 

 elevated to the level of the last whorl; whorls three, nearly round, 

 being a little wider and flatter above than below, the first two and 

 two-thirds in contact and having a deep suture above and below, the 

 last third of the outer whorl solute, leaving the penultimate whorl at 

 a tangent, the free part very slightly deflexed ; on the inner side of 

 the uncoiled part of the shell, close to the penultimate whorl, there is 

 generally a well-marked groove ; surface with close, delicate incre- 

 mental striaj which are crossed by microscopic threads that run par- 

 allel with the direction of the whorls ; aperture nearly circular, com- 

 pressed a little on the inner side ; peristome scarcely thickened or 

 reflexed; epidermis greenish -yellow. Height 1.5, greatest diameter 

 5, diameter at the point where the last whorl becomes free 4 mm. 



Seven dead specimens were found on the mountain of La Ferriere, 

 in northern Haiti, at an elevation of perhaps two thousand feet, in a 



