ball: mollusca and brachiopoda. 293 



periphery, where they form angular projections, obsolete on the last half of the 

 last whorl, beeoniing obsolete midway between the periphery and the canal ; 

 the upper surface of the whorls flattish, sloping, Avith about fifteen fine, close, more 

 or less alternated spiral threads; periphery with a strong projecting spiral keel 

 more or less angulated by the ribs at their intersections ; in front of the keel are 

 about fifteen primary spiral ridges, low, with wider interspaces ; both the ridges and 

 the interspaces sculptured with finer subequal close secondary threads, except ou 

 the canal where they alternate; aperture elongate, angulated by the keel; anal 

 sulcus wide, shallow; outer lip sharp, thin, crenulated by the spiral sculpture; 

 body witli a thin wash of callus ; pillar straight, obliquely truncate in front ; 

 canal moderately long, rather wide and sliglitly flaring at the end ; operculum 

 none. Lon. of shell, 11.5; of last whorl, 8.0; of aperture, 6.2 ; max. diam. 

 6.5 mm. 



U. S. S. " Albatross," station 3393, Gulf of Panama, in 1020 fathoms, mud, 

 bottom temperature 36°.S F. U. S. N. Mus. 123,130. 



The shell is probably not fully grown, and the character of the aperture may 

 be somewhat different at maturity. 



Clinura peruviana Dall, n. sp. 



Plate 13, figure 2. 



Shell small, white, with a thin grayisii pcriostracum and about five similarly 

 sculptured whorls exclusive of the (lost) nucleus; axial sculpture of (on the last 

 whorl thirteen) sharp, narrow, vertical ribs, feeble and concavcly excavated be- 

 tween the suture and the keeled shoulder of the whorl, there prominently angular, 

 beyond the shoulder vertical, becoming obsolete on the base ; beside this the in- 

 cremental lines are minutely elevated and rasp-like over the whole surface, but 

 most so between the spirals; suture distinct, not appressed, the whorl between 

 it and the shoulder descending and flattened, with five or six revolving fine 

 tiireads and some secondary, finer intercalary tli reads ; shoulder with a prominent, 

 small, rounded keel, undulated by the ribs, beyond which similar spiral threads to 

 the number of a dozen or more, with wider interspaces, to the canal ; the first in- 

 terspace has three equal fine intercalary threads, the second two, and the remain- 

 der one each, becoming gradually closer anteriorly; aperture rather narrow, the 

 anal sulcus wide, shallow, extending from the shoulder to the suture ; aperture 

 angulated by tlie shoulder keel; outer lip thin, entire; body with a wash of cal- 

 lus, white, polished ; pillar rapidly attenuated, straight, axis not pervious ; canal 

 narrow, straight. Lou. of shell, 9.0; of aperture, 5.2 ; of last wiiorl, 7.0; max. 

 diam. 4.2 mm. 



U. S. S. "Albatross," station 4654, 24 miles N. 6S° W. from Point Agujn, 

 Peru, in 1036 fathoms, mud, bottom temperature 37°-3 F. U. S. N. Mus. 

 110,564. 



