19 



but deep umbilical depression, and become gradually more faintly 

 marked until the two upper ones are nearly obsolete. Above, and 

 next to the suture, there is a faint revolving and rather wide groove, 

 which is succeeded by a broad smooth band. The whole surface of 

 the body-whorl is also crossed by numerous oblique strise of growth. 



Although the words " umbilicus none " occiu- in the original definition 

 of the genus Cyclonema,'* yet as the C. sulcata is distinctly described bj^ 

 Pi-of. Hall as having a small umbilicus, it is clear that this generic 

 character will have to be modified so as to include species with a small 

 umbilical perforation which does not expose any part of the inner 

 whorls, — or else that the present species should be removed to some 

 other genus, for which procedure there does not seem to be any 

 sufficiently adequate reason. In the writer's judgment also, the 

 Trochonema pauper of Hall and the Cyclonema sulcata of the same 

 author ought not to be placed in different genera. 



Trochonema inornatum. (N. Sp.) 

 Plate 3, fig. 7. 



Shell angularly turbinated, depressed, much broader than high ; 

 whorls from three to four, increasing very rapidly in size ; spire step- 

 shaped, moderately elevated, occupying rather less than one-halt the 

 entire height, its volutions flattened above and obliquely compressed 

 at the sides ; body-whorl flattened both above and below nearly at a 

 right angle to the axis of the shell, and compressed laterally and 

 somewhat concavely in the middle, — biangulated, its upper portion 

 being distinctly shouldered, and its basal margin rather less distinctly 

 so ; umbilicus very small, or perhaps entirely closed when the whole 

 of the test is preserved ; apertm-e evenly rounded on the inner or 

 columellar side and rather obscurely biangular externally. Test 

 moderately thick ; surface nearly smooth but marked by fine transverse 

 lines of growth, which are distinctly insinuated on the superior angle 

 of the body-whorl. 



Breadth of the most perfect example collected, twenty-four milli- 

 metres ; entire height of the same, twenty mm. ; height of the spire 

 only, nine mm. 



Elora : E. Bell, 1861 : one specimen, with most of the test preserved. 

 Dui-ham, Mr. J. Townsend : a single cast. 



The best specimen has most of the shell broken away in the umbilical 

 region, so that it is uncertain whether the base was imperforate or 



* On page 89 of the second volume of the Palaeontology of the State of New 

 York. 



