2 PROCEEDINGS OF TKE NATIONAL MUSEUM vol. GO 



Cuming and published in 1834 by Sowerby in the Proceedings of the 

 Zoological Society of London (pp. 6-8.) They are: 



Eulima spleiididula^ E. imhricata^ E. hastata^ E. pusilla. 



These I referred to the following genera in my Monograph of West 

 American Melanellicl Mollusks, published in 1917 in volume 53 of 

 the Proceedings of the Ignited States National Museum : 



Niso splendidula Sowerby (p. 348, pi. 48, fig. 5). 



Niso imiricata Sowerby (p. 351, pi. 48, fig. 6). 



MelaneUa (Melanella) hastata Sowerby (p. 317, pi. 38, figs. 4, 6). 



Mclanella (MelaneUa) i)usiUa Sowerby (p. 317, pi. 38, fig. 2). 



PYKAMIDELLA (PHARCmELLA) AVA, new species 



Plate 3, fig. 6 



Shell minute, stout, pupoid. Nuclear whorls decollated. Post- 

 nuclear wdiorls slightly rounded, smooth, marked b}^ faint riblets, an 

 occasional varicial streak, and a single deeply incised peripheral 

 spiral groove which is crossed by slender axial threads. This groove 

 falls considerably anterior to the summit of the succeeding turns, 

 leaving a rather broad smooth band between this incised line and 

 the suture. Base well rounded, marked by a continuation of the 

 slender riblets and microscopic spiral striations. Aperture oval; 

 outer lip reinforced within by seven spiral lamellae; columella very 

 stout, short, provided with a strong oblique fold at its insertion, and 

 two very slender much more oblique folds anterior to this. 



The type (Cat. No. 363067, U.S.N.M.) has lost the nucleus and 

 probably the first postnuclear whorl. The four and one-half remain- 

 ing whorls measure, length, 4.1 mm. ; diameter, 1.6 mm. 



PYKAMIDELLA (TRIPTYCHUS) OLSSONI, new species 



Plate 1, fig. 11 



Shell moderately large; semitranslucent, bluish- white. Nuclear 

 whorls decollated; postnuclear whorls moderately rounded, strongly 

 tabulatedly shouldered at the summit, marked b}' three strong 

 rounded spiral cords, of which the first, which is at the summit, 

 is a little stronger than the other two; the third is about as far 

 anterior to the suture as it is distant from the median. In addition 

 to the spiral cords, the w^horls are marked by axial ribs wdiich are 

 more strongly developed on the anterior half of the whorls than on 

 the posterior. On the anterior half they cause their junction with 

 the spiral cords to form decided tubercles which are best developed 

 on the median cord; the third cord is not affected by the ribs as far 

 as the formation of the tubercles is concerned, and appears almost 

 smooth; the space between the median and the third cord, and the 



