152 HELICOPHANTA. 



Spermatheca with a long duct, closely bound to the vagina (PI 

 49, fig. 21, H. magnified showing penis and lower portion of uterus 

 and spermatheca duct. Fig. 20, reverse side of female side, show- 

 ing vas deferens, etc. Fig. 22, penis split along line a-b in 

 fig. 21, showing cavity. Fig. 23, section of enlarged wall of penis 

 along Mne c-d of fig. 22, showing vesicular structure beyond the 

 entrance of the vas deferens. PI. 49, fig. 18, genitalia of H. goudo- 

 tiana, after Brancsik. 



The peculiar features of this genus are the very large size of the 

 shell and its extremely large embryonal or nuclear portion ; the 

 great thickness of the fleshy mantle-edge, and the peculiar structure 

 of the penis. The unicuspid teeth of the entire radula, and the 

 smooth jaw, are characters common to Acavus, Panda, and other 

 allied genera. The species are restricted to Madagascar, but the 

 affinities of the genus are entirely with groups of the Seychelles 

 Islands and Ceylon. It is not yet known whether the young are 

 brought forth alive as in Stylodonta, or in eggs as in Acavus, Panda 

 and Borus. 



That Ferussac intended his group Helicophanta especially for the 

 glassy, vitrinoid shells subsequently called Daudebardia, is evident 

 from his definition, grouping, and the etymology given ; and some 

 authors have used the name for these forms. But as Beck, Albers 

 and v. Martens have chosen another course, it seems advisable to 

 follow the precedent of such high authorities, especially since, by 

 the " law of elimination," the same result is obtained. The only 

 other course open to us would be to replace Daudebardia by Heli- 

 cophanta, and use the term Macroon in a restricted generic sense for 

 this Madagascar group. 



The anatomy of Helicophanta is known by Seinper's description 

 of H. magnifica (Nachrbl., 1880, p. 60), and by a figure of the geni- 

 talia of H. goudotiana by Brancsik (Jahresheft des Naturwissen- 

 schaftlichen Vereines des Trencsener Comitates, 1892-3, p. 209, pi. 

 6, f. 5. The writer has examined H. magnifica in the flesh, and the 

 figures on plates 48 and 49 are drawn from this specimen. 



Group oj cornugiganteum 



H.cornugiganteum Chemn.vi, 60. H. guestieriana Cr., vi, 62. 



H. betsileoensis Ang., vi, 61. H. vesicalis Lam. 



H. ibaraoensis Ang., vi, 61. bicingulata Smith, vi, 63. 



