44 ANNALS NEW YORK ACADEMY OF SCIENCES 



The second volution is like the first, except that it has a third weaker 

 spiral just below the suture and numerous ribs are present at this stage. 

 On the sixth volution of those preserved the sub-sutural spiral becomes 

 nearly as 'strong as the two primary spirals, and all three become strongly 

 nodose where crossed by the ribs. On the next two volutions the shoulder 

 practically disappears, and the volution seems to be ornamented by three 

 rows of strong nodes with intercalated spirals between them. Varices 

 are irregularly developed from the fifth volution onward and on the later 

 whorls become extremely prominent, forming a conspicuous feature of the 

 ornamentation. Both ribs and varices are set at an angle with the verti- 

 cal axis of the shell, so that they appear to twist in passing from whorl to 

 whorl. On the tenth volution of those present the two lower spirals 

 again become more prominent than the sub-sutural row, giving an oblique- 

 angled outline to the volution, which has vertical sides and a row of strong 

 nodes on the shoulder. Rather coarse intercalated spirals cover all the 

 surface between the rows of nodes. Just above the suture a row of fine 

 nodes is partially concealed by the succeeding whorl. On the body volu- 

 tion the shoulder is nearly obsolete, and there are six rows of nodes, of 

 which the two upper are the strongest. A very strong varix is present 

 on the side opposite the outer lip. 



The aperture is elongate oval, with a narrow, thick callus and well-de- 

 veloped posterior tooth. The outer lip in some individuals is extremely 

 thick, and the aperture in these specimens is somewhat constricted by the 

 addition of material to the inner margin. Other specimens do not show 

 such thickening of the lip. The siphonal canal is short and slightly re- 

 flexed at the margin. At an earlier stage of growth the canal was bent 

 toward the left, but the animal has abandoned this position and continued 

 the canal in a downward direction, the earlier growth being left as a 

 curious knob on the outside of the tube. 



Horizon and locality : Miocenic. Martillac near Bordeaux. 

 No. 20141. Columbia University collection. 



Eemarks : This species bears a striking resemblance to the Florida 

 species, C. glnphyrea. in the closely set ribs, the number of the spirals 

 and the form of the aperture ; but it differs in being a more closely coiled 

 form and in having numerous very strong varices. 



This species has been made the type of a new genus, Chondrocerithium, 

 the distinguishing characteristics being the presence of a columnellar pli- 

 cation and slight differences in the aperture. The development of the 

 species shows its close relationship to Oerithivm.. and the aperture does not 

 differ in any essential respect from many species of that genus. A faint 



