542 BULLID7E. 



external volutions. Its inilU-wliite surface is adorned by 

 a kind of lacework, composed of very numerous and close- 

 set scarcely raised spiral costellaj, so regularly serrated at 

 both edges that their intervals assume the appearance of 

 suboval, though somewhat irregularly formed, confluent 

 impressed dots, the series of which are alternately larger 

 and smaller, yet always narrower than the raised sculpture. 

 This alternation gives to the costella?, which beneath a 

 powerful lens seem traversed by most minute spiral striula?, 

 and which are so very flat that the sculpture might more 

 briefly be described as consisting of alternately larger and 

 smaller series of confluent punctures, the appearance of 

 being double or subdivided in the middle by a string of 

 minute impressed dots. The wrinkles of growth are occa- 

 sionally very conspicuous. The aperture is very ample, 

 filling nearly three-fourths of the ventral area ; it is of a 

 broad and stunted pear-shape, the posterior contraction 

 being very short, and not acute. The outer lip, which is 

 rounded posteriorly, where it rises a little above the level 

 of the crown, advances and becomes retuse or incurved in 

 a line with the contraction of the body, and projects in a 

 somewhat arcuated fashion below ; at the anterior extre- 

 mity the curve is so little rounded as to give an obliquely 

 subtruncated look to the base of the aperture. The coat- 

 ing of enamel upon the body is rather extensive, and the 

 incurvation of the pillar lip, which is reflected above, and 

 somewhat indented, yet not unibilicated at the axis, is much 

 extended, as the portion of the body which juts into the 

 aperture is very short. One of the examples measured 

 nearly a quarter of an inch long, and was about two lines 

 and a third broad. 



In a variety taken by Mr. M'Aiulrew, whose scientific 

 dredging has thrown much light upon the boreal deep- 



