CYLINDRA. 197 



C. DACTYLUS, Linn. PL 57, figs. 658, 664. 



Spire decussated, body-whorl with sometimes a slight shoulder. 



Whitish, clouded with chestnut-brown ; encircled with distant, 

 narrow, closely punctate, incised brown lines. 



Length, 1-25-1-75 inches. 



Philippines; Polynesia ; sand or sandy mud inside the reefs. 



G. obesa, Reeve, is a specimen covered with its greenish 

 epidermis, and C. Potensis, Montr, (fig. 661) is a small, more 

 cylindrical variety from New Caledonia. 



C. ORNATA, Schuberth and Wagner. PL 57, fig. 660. 



Thick, white, with close revolving series of red punctae. 



Length, 1-5 inches. 



Habitat unknown. 



I have copied the poor figure of this species which has been 

 passed over by both Reeve and Sowerby. Very probably it = 

 G. dactylus. 



C. CRENULATA, Gmelin. PL 57, figs. 662-666. 



Cylindrical, with impressed, closely pitted revolving lines ; 

 white, with waved clouds of chestnut-brown, frequently disposed 

 in two or more broad interrupted bands of large spots. 



Length, 30-40 mill. 



Red Sea, Indian Ocean, Mauritius, Philippines, Polynesia. 



C. undulosa, Reeve (fig. 664), differs typically in six or eight 

 of the revolving lines being colored, and the form is not quite so 

 cylindrical ; it is connected by intermediate stages with C. crenu- 

 lata. In C. radula, Sowb. (fig. 665), the form, and in some cases 

 the coloring, of C. undulosa are preserved, but the growth-lines 

 are close and deep, decussating the revolving lines and forming 

 numerous little square tubercles at their intersection ; this also 

 gradually shades off into the smoother typical form. It is not 

 unliktely that this rough form will be found to be a connecting 

 link in a chain of variations uniting C. crenulata with G. fenes- 

 trata. G. arctata, Sowb. (fig. 666), is a variety with more pro- 

 duced spire, and two interrupted brown bands ; it is included in 

 the series of specimens before me. 



