Occasional Papers of the Aliisciim of Zoology 3 



checnsis Conrad {prcvostianus Lea) and is about midway be- 

 tween that species and L. niodioliforuiis Lea and may best be 

 considered a variety of the former." 



Through the courtesy of Mr. Mazyck I have had the oppor- 

 tunity of examining these specimens and have had them photo- 

 graphed and they are reproduced on pi. I, figs. 1-4. 



While in Washington and Philadelphia in 1918 I took occa- 

 sion to compare the Lewis examples with those in the National 

 Museum and the Philadelphia Academy and found that they 

 agreed exactly with those in these collections. 



As stated by Simpson, there are two sets representing dif- 

 ferent species in the Lea Collection under the name of ten ems 

 Rav. One is undoubtedly the viodiolifonnis of Lea and the 

 other is the species represented by Ravenel's own specimens 

 and that figured by Simpson in his Florida paper. 



Simpson, no doubt, was lead to change his opinion as to 

 what was really Ravenel's tencrus by the fact that Lea in his 

 synopses had placed it next to or near his modioliformis. 

 But the fact that Lea distributed the other species as "tenerus 

 Rav.'' would go to show that he considered that to be really 

 Ravenel's species. 



Both of Ravenel's specimens are females and that repre- 

 sented by figs. I and 2, being mature, may be considered as the 

 type. It has written on the inside of the right valve in Raven- 

 el's handwriting, "[/. tenerus Ravenel — female." It measures: 

 length 52, alt. 32, diam. 21 mm. It is a thin shell, smooth, 

 yellowi.sh-brown with darker rest-marks, deeper brown to- 

 wards the beaks, faintly rayed with green ; the beaks are 

 eroded ; the right valve has a thin, triangular and erect pseudo- 

 cardinal tooth and an obsolete second one and a single lateral, 

 low, long, thin and straight; the left valve has two pseudo- 

 cardinals, thin, erect and nearly in the same line and two lat- 



