COLUMNA. 121 



teriorly the foot is flattened above (pi. 44, fig. 7, C. columna, 

 after Rang) . Egg capsules oblong and a little arcuate, light 

 yellow, three or four being found in the uterus (pi. 44, fig. 

 6, C. columna, after Rang). Internal anatomy unknown. 



Type C. columna Mull. Distribution, islands in the Gulf 

 of Guinea. Prince Island is the only well attested locality 

 for Columna; but on more or less doubtful authority, Cape 

 Palmas and Grand Bassam, mainland points, have been 

 given. They live on the ground, under leaves and fallen 

 wood, in moist valleys in the mountains. 



Columna is closely related to Archachatina, from which it 

 is differentiated chiefly by the lengthening and looser coil of 

 the whole visceral mass and shell, while meantime the color- 

 ation and system of sculpture remain unchanged. Archacha- 

 tina is the acme of its phylum, while Columna is a lateral 

 branch with phylogerontic characteristics. Insular stocks 

 often hasten to complete their cycles, perhaps owing to the 

 stereotyped environments. Most island faunas of any antiq- 

 uity show an undue proportion of senile types. 



Key to Species. 



1. Columella projecting in a callous flange above, spirally 



ascending, the axis seen to be hollow in a basal view; 

 surface of shell strongly decussate-granose. 



C. columna, no. 1. 



2. Columella appressed above, not projecting; no axial hole 



seen in a basal view. Surface smooth or nearly so. 



a. Shell elongate, the surface very minutely, subob- 



soletely decussate. C. leai, no. 2. 



b. Shell shorter, the last whorl more gibbous, the sur- 



face smooth. C. hainesi, no. 3. 



1. C. COLUMNA (Miiller). PL 46, figs. 5-9. 



Sinistral, pillar-shaped, moderately solid; yellow or dirty 

 yellowish-white, profusely marked with red-brown stripes, 

 which on the upper, part of each whorl are weak, split and 

 interrupted or obsolete; the apical whorls being dull and 

 red-brown. Surface is closely granulose throughout by the 



