76 BULLETIN OF THE 



Leucosyrinx Sigsbeei Dall. 



Plate XI. Fig. 10. 



Pleurotoma (Pleurotomellal) Sigsbeei Dall, Bull. M. C. Z., IX. p. 57, August, 1881. 



Habitat. Station 33, 1568 fms., Yucatan Strait, G40 fins, (young). Station 

 236, off Bequia, living in 1591 tins., ooze, bottom temperature 39°.0 F. 



The differences between this and the last species were noted in the original 

 description. Both species have moderately small subglobular glassy inflated 

 nuclei, not large enough to give a mamillary look to the apex, but larger than 

 in the average Pleurotoma. In both, the fine spiral threads cover the whole 

 fasciole and there is no coronet in front of the suture. 



Leucosyrinx tenoceras n. s. 



Plate XXXVI. Fig. 5. 



Shell long, very slender, the aperture longer than the spire behind it ; white 

 or ashy, the nucleus yellowish, subglobular, glassy, smooth ; whorls ten, beside 

 the nucleus ; suture appressed, a coronet of short, elevated, backward pointing 

 wrinkles marginating the whorl in front of it; fasciole wide, with obsolete 

 sculpture or smooth, polished, very sloping, subconcave ; shoulder of the 

 whorl angulated, ornamented (on the whorl before the last) with about four- 

 teen nodular riblets ; these riblets on the early whorls are short, stout, and 

 very prominent, later they become more slender and oblique, and on the last 

 whorl tend to become obsolete entirely ; the whole shell except the fasciole is 

 covered with fine flattened threads, not prominent, and often wavy or obliquely 

 directed from irregularities of growth ; aperture long, rather narrow ; canal 

 narrow, long, flaring a little at the end ; outer lip thin, simple, broadly arched 

 forward, with no internal lira ; notch deep, very wide, extending from the 

 suture to the shoulder ; pillar lip slightly excavated, white, smooth ; pillar 

 straight, attenuated in front ; whorls moderately full, having a drawn-out 

 appearance ; operculum thin, pear-shaped, acutely pointed, with a thin mar- 

 ginal rib ; pale horn-color. Lon. of shell, 60.0 ; of last whorl, 40.0 ; of aperture, 

 33.0; max. lat. of shell, 14.0 mm. 



Habitat. Station 161, near Guadalupe, in 583 fms., sand, temperature 41°. 0. 

 Station 265, near Grenada, in 576 fms., ooze, temperature about 40°. 0. Also 

 at U. S. Fish Commission Station 2392, in 724 fms., mud, Gulf of Mexico 

 between the Mississippi delta and Cedar Keys, Florida, temperature 40°.7 ; 

 and Station 2677, off Cape Fear, North Carolina, in 478 fms., mud, temperature 

 39°.3 F. 



This is more slender than either of the preceding species, and has a smoother 

 and always coronated fasciole, which rarely shows spiral sculpture. 



