396 MAZATLAN UNIVALVES: 
Only one specimen, not quite mature, was found of this 
species, which resembles D. aterrima, zonulata, &c. but is 
easily recognized by the non-excavation and extremely faint 
keeling of the area of the sinus; and the colour, which pre- 
sents one large and several minute rows of connected orange 
tubercles upon a black ground. Long. °64, long. spir. *Al, 
lat. ‘23, div. (anfr. prim.) 30°. 
Hab.—Mazatlan ; 1 fresh adolescent sp. ; Z’pool Col. 
Tablet 1899 contains the specimen. 
465. DRILLIA ALBOVALLOSA, 7%. s. 
D. t. adolescente subturrita, nigra; costd rotundatd, albida, 
expressd, spiram ascendente ; marginibus spire subineuvrvatis ; 
totd superficie confertim spiraliter striulatd, striulis in aream 
sinus haud excavatam magis expressis; costa albd suturam 
approximunte, haud attingente, undato-tuberculata ; serie tuber- 
eulorum, circiter xvil., angustorum, radiatim elongatorum, viz in 
spird monstrante ; striis spiralibus circa basim, quarum super- 
tores tuberculose, tuberculis alteris convenientibus : t. adulta 
anfr, i1.--iv. omnino coste albe carente ; vice ejus serie tuber. 
culorum infrasuturalium, tuberculis peripherialibus anfractus 
alterius convenientium; anfr. ult. parum descendente ; mar- 
ginibus spire excurvatis ; aperturd subovali ; sinu postico lato, 
haud profundo ; nigro-fuscd, prope sinum posticum maculis 
subdiaphanis ornaté. 
Only one specimen of this shell was found in the Mazatlan 
collection. The spire is rather compact, last whirl somewhat 
projecting, white band not quite touching the suture, and 
peripheral tubercles shewing more in the early than in the 
latter whirls. A specimen of unknown locality in Dr. Gould’s 
collection appears to be conspecific, but is larger, spire rather 
more elevated, markings not so decided (perhaps rubbed) and 
with the band smooth and yellowish. A shell however appears 
in the Cumingian Museum, of uncertain history, which begins 
exactly like the Mazatlan specimen, with the white ridge 
round about six whirls; after which it suddenly changes, 
developing three whirls and a half without any white ridge, 
and presenting the general appearance of D. rudis. Even this 
specimen is not quite mature, as is shewn by the sharp un- 
formed labrum. The faint, semi-transparent spots above the 
tubercles round the periphery are only seen by holding the: 
