I02 Bulletin 39 274 



A single specimen from the Island of Bocas (Columbus or 

 Colon Island) is here figured. It differs from the Mitra longa, 

 in being shorter and broader. The sculpture is less elegant. 



Length 21, diameter 7, last whorl 14, spire 11 mm. 



Gatun Stage: Gahin, C. Z. 



Bocas del Toro, Panama. 



iWitra aff. rudis Gabb Plate 6, figure 13 



Mitra i^udis Gabb, 1873, Trans. Amer. Phil. Soc. , vol. 15, p. 220. 



Shell subfusiform, biconic; whorls about 7, coarsely sculp- 

 tured with strong, revolving cords, separated by interspaces of 

 about twice their width; These interspaces are finely longitudi- 

 nally sculptured with raised threads above, obsoletely so below; 

 the spire-whorls have 5 cords, the last whorl with 1 1 and several 

 smaller ones on the canal; aperture subelliptical, with a thin out- 

 er lip; columella with 4 plaits, largest above; anterior canal of 

 medium length, strongly twisted below. 



Length 33.5, diameter 12.5, last whorl 24, spire 16 mm. 



It is with much uncertainty, that I have identified this rare 

 species with Gabb's unfigured Mitra rudisixovn Santo Domingo. 

 Gabb,s descriptions and measurements indicate a shell of much 

 the same characters as well as dimensions. 



Gatu7i Stage: Coll. j, Ho7ie Walk Creek, C. R. 



Mitra poas, n. sp. Plate 6, figures 20, 21 



Shell small, nearly smooth and columbelloid in appearance; 

 whorls 8, with straight sides; last whorl widest just above the 

 base, which is contracted to the short anterior canal; the early 

 spire-whorls have 5, low, smoothish spiral bands, with longitudi- 

 nally sculptured, narrow interspaces; these spirals quickly be- 

 come obsolete, leaving the whorls smooth except for one or two 

 spirals bordering the upper sutures; the last whorl has about 4 

 spirals around the base and smaller ones on the canal; aperture 

 subellipical, with a thin outer lip; columella with 4 plaits, larg- 



