94 MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
Range. San Pedro to San Diego, California; also Pleistocene. 
This was described as Pleurotoma ( Borsonia) bartsch by Arnold. 
Borsonella nychia Dali, 1919 
Proceedings of the United States National Museum, 56:38; Pi. 12, fig. 2. 
Shell white, with an olivaceous periostracum, biconic, acute, the 
nucleus (eroded) of one or two whorls, with about six subsequent whorls, 
rapidly enlarging, flatly descending from a distinct, not appressed suture 
to the periphery and with the last whorl conically attenuated in front; 
spiral sculpture of an obscure thickening in front of the suture; fine rather 
irregular striae thence to the periphery, crossed obliquely by irregular 
scratches, a prominent angle at the periphery, which on the spire is just 
behind the suture, and on the last whorl is ornamented with nine or ten 
prominent nodules with wider interspaces; on the base the striae are 
coarser and more irregular, the interspaces assuming the form of (about 
15) flattish threads, sparser on the canal; axial sculpture of fine incre¬ 
mental lines arcuate on the anal fasciole; aperture elongate triangular, the 
anal sulcus very wide and shallow, outer lip thin, sharp, smooth within, 
arcuate in front of the periphery; inner lip erased, pillar solid, short, with 
a single plication near the body, attenuated in front, straight; canal hardly 
differentiated, somewhat produced. Height of shell, 12; of last whorl, 8; 
diameter, 5.5 mm. (Dali.) 
Type in United States National Museum, No. 208891. Type locality, 
Station 4361, off Point Loma, California, in 101 fathoms. 
Range. Off Point Loma, California, in 101 fathoms. 
Borsonella civitella Dali, 1919 
Proceedings of the United States National Museum, 56:302. 
Shell fusiform, elongate, acute, of a pale buff color, of eight or more 
whorls, the nucleus defective, the suture distinct, not appressed; axial 
sculpture of (on the penultimate whorl, nine) short, prominent ribs con¬ 
spicuous only on the periphery and obsolete on the later part of the last 
whorl; the incremental lines are also rather conspicuous; there is no spiral 
sculpture except a few faint lines on the anal fasciole which is adjacent to 
the suture; in addition to the above there are minute oblique striae often 
punctate, with wider interspaces which cross the incremental lines almost 
at right angles; these, hardly visible except under a lens, give the surface 
a vermiculate aspect; aperture rather narrow, the anal sulcus wide and 
shallow, the outer lip strongly protractively arcuate, thin, simple; inner 
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