122 BULLETIN OF THE 



Habitat. Station 2125 of the U. S. Fish Commission, near Curasao, in 208 

 fnia., sand, bottom temperature 51° F. 



This line shell in its simplicity of sculpture and wide sweep of the peristome 

 from the notch along the outer lip is quite unparalleled by any of the known 

 species. Its nearest relative is P. Bairdii Verrill, which is stouter, with a 

 much shorter spire and coarser spirals, beside having a shallow notch, distinct 

 transverse ribbing, and no distinct carina. P. Edgariana is much more spindle- 

 shaped. It is named in honor of Mr. Edgar A. Smith, the well known con- 

 chologist of the British Museum. Gymnobela engonia Verrill, and some other 

 forms which are considerably smaller, have somewhat the general aspect of 

 this species, but all are stouter in proportion. 



Pleurotoraella Emertonii Verrill & Smith. 



Plate X. Fig. 9. 



Pleurotomella Emertonii V. & S., Trans. Conn. Acad., VI. p. 154, pi. xxxi. fig. 6, 



April, 1884. 



Habitat. Station 121, between St. Thomas and Santa Cruz, in 2393 fms., 

 gray globigerina ooze, bottom temperature 39°. 5 F. 



This line specimen, which measured 34.0 mm. in length, is one of the most 

 delicate and beautiful shells obtained by the expedition, and was obtained from 

 the deepest water of any of the Blake shells. 



Pleurotomella chariessa Watson. 



Pleuroioma (Defrancia) chariessa Watson, Linn. Soc. Journ., XV. p. 458, Nov., 1881. 

 Clathurella chariessa Watson, Chall.Brach., p. 352, pi. xx. fig. 6, 1885. 

 Pleurotomella Jeffreysii Verrill, Trans. Conn. Acad., VI. p. 411, pi. xliv. fig. 3, 1885. 



Habitat. Station 163, off Guadelupe, in 769 fms., sand ; Station 173, near 

 the last, in 734 fms., ooze ; Station 230, off St. Vincent, in 464 fms., fine sand; 

 Station 236, in 1591 fms., ooze, near Bequia. Bottom temperatures 39° to 41° F. 

 Also off Martha's Vineyard, in 1537 fms.; off Delaware, in 1168 fms. ; east 

 from George's Banks, in 1710 fms.; off North Carolina, in 731 fms., and off 

 Jamaica, W. I., in 966 fms.; U. S. Fish Commission. North Atlantic sea-bed 

 in 350 to 1125 fms., from western Europe to the American shores. 



This is another one of those species which appear to luxuriate in variation, 

 and which, if we had only material enough, would make the student pause 

 to inquire what common criterion of species he is to adopt for conditions so 

 different as those of the shallow water and the archibenthal forms respectively. 



Among those forms in the collection before me which I regard as too 

 closely connected to be separable as species, the following varieties can be 

 recognized : — 



i 



