60 EPIROBIA. 



gradually becomes larger. On the middle and outer mar- 

 ginals the ectocone is split, the teeth being thus low and wide, 

 with two deeply bifid cusps, not differing much in length. 



In E. berendti (pi. 20, fig. 4) Strebel shows somewhat 

 pointed mesocones, the central tooth with the ectocones con- 

 crescent with the main cusp. Formula 27.1.27. I have some 

 doubts of the correctness of the figure, and strongly suspect 

 that Strebel transposed the radula of E. berendti and Holo- 

 spira goldfussi. 



Type, E. polygyra (Pfr.). Distribution, eastern and south- 

 ern Mexico (States of Vera Cruz and Chiapas) and northern 

 Guatemala. 



This group is related to Holospira, differing chiefly in the 

 greater attenuation and lengthening of the shell, and espe- 

 cially in the more slender early whorls. The radula however 

 is more and differently specialized in Epirobia, both ento- and 

 ecto-cones being developed in the teeth of the median field, 

 basal in position and separated from the very large, rounded 

 mesocones; while in Holospira the teeth of the median field 

 have single, simple, conic cusps. The Lower Californian 

 group Spartocentrum has the same general contour, persistent 

 spire and hollow axis, but in that group the early whorls are 

 sculptured and the internal pillar smooth, while in Epirobia 

 the nepionic shell is smooth and the pillar roughened. There 

 is great external resemblance to the species of Brachypodella 

 inhabiting the same districts, but these have a slender, imper- 

 forate axis, and a keeled base, while Epirobia has a hollow 

 axis and a rounded base. Crosse & Fischer and von Martens 

 seem to have been unaware of the difference in internal struc- 

 ture, as they mingle the species of Brachypodella and Epirobia 

 without regard to it. Strebel fully grasped the significance 

 of the structure of Epirobia in his work of 1880. 



The internal pillar has sculpture fundamentally like Gcelo- 

 stemma and even more like typical Ccdocentrum; but the rib- 

 lets have been much interrupted, so that in some species they 

 are hardly recognizable as such. 



The genital system requires re-examination with fresh ma- 

 terial, Strebel's work thereon having been based upon dried 



