J 899.] NATURAL SCIENCES OF PHILADELPHIA. 157 



Length of the largest example, 6f mm. ; diameter, 14 mm. ; 

 length of aperture. If mm. 



Three specimens (No. 62,800) from AVest Florida were pre- 

 sented by Mr. C. W. Johnson, 1891. 



The more slender Turbonilla virga Dall is a closely related 

 species In a specimen sent to me by Dr. Dall, the 10 flattened 

 whorls (nucleus wanting) are much more gradually tapered so that 

 it is but about one-half as svide as an example of incisa of the same 

 length and the 7 incised Hues are equal, and under the microscope 

 appear to cut into the sides of the transverse ribs. 

 Turbonilla incisa variety constricta, new. 



Two specimens (No. 79,023) from the same locality are of mod- 

 erate size, slender, irregularly coiled (abruptly contracted in the 

 6th and 7th whorls), semitransparent, pale yellow (when fresh), 

 with a broad band of brown on the base, and a fainter one at the 

 suture. Upper whorls moderately convex, lower ones flattened. 

 Suture well marked. Whorls 10 below the prominent, oblique, 

 flattened nucleus. Transverse ribs irregularly developed, thin, 

 narrow, but little raised, separated by wide, shallow spaces. On 

 the 5th whorl, the interspaces are wide, but become much nar- 

 rower on the 6th whorl with more delicate and more numerous ribs, 

 while on the 8th whorl they again become wider, with much 

 stronger ribs; and on the last whorl the ribs number about 26. 

 Base well-rounded, cut by about 7 fine, incised, unevenly sep- 

 arated, spiral lines, the upper one the most distinct. Aper- 

 ture ovate ; pillar-lip thin, well reflected. The spirals on the 

 upper whorls are arranged as in typical incisa, but on the lower 

 ones, in the larger specimen, they number 7, but are of equal 

 size, and evenly spaced; under the microscope 2 or 3 finer ones 

 appear below the suture, and on the middle of the whorls; also on 

 the lower portion of the, base, numerous, still finer ones. When 

 young, this variety could not be separated from the typical exam- 

 ples, but the peculiarity in its development, seen even in one with 

 7 whorls easily distinguishes it, at least as a variety. 



Length of the larger specimen, Q^ mm.; diameter, 1.5 mm.; 

 length of aperture, li mm. ^ 

 Turbonilla elegans Verrill (?) variety (?). 



Turbonilla elegans Verrill. Amer. Jour. Sci., iii, p. 282, PI. VI, fig. 4, 

 1872; Invert. Aui. Vineyard Sound, p. 363, PI. XXIV, fig. 155, 1874. 



