266 PYRAMIDELLIDJE. 



guage of the " Testacea Britannica " does not precisely 

 correspond with the characteristics of the present spocies. 

 The Terehra speciosa of Bean was constituted from an 

 individual which had received an injury to its aperture. 



It is not easy to circumscribe the limits of this species, 

 which has compelled us to examine and mutually compare 

 a considerable number of specimens in order to determine 

 the value of a character (the degree of volutional con- 

 vexity), which elsewhere seems of specific, but here of mere 

 varietal importance. 



Living specimens of this curiously carved shell are 

 rather thin, and of an uniform somewhat glossy and semi- 

 transparent white. The shape is turreted-subcylindrical, 

 and rather stunted ; the apex is more or less obtuse. The 

 whorls, which are seven or eight in number, enlarge but 

 slowly, are fully half as large again as high, and are 

 separated from each other by a well marked and not very 

 oblique suture. They are crowded with very numerous 

 and obliquely flexuous depressed costellaj that arch below 

 to the left (if viewed dorsally), but slant a little in the 

 opposite direction above, where they generally become 

 confluent, and look as if hammered down ; a peculiarity 

 that sometimes causes the sutures to appear succeeded by 

 a smooth rim. The interstices, which for the most part 

 are narrower than the ribs themselves, are more or less 

 distinctly traversed by a few elevated spiral lines, that 

 generally (if not always) become faint or obsolete upon the 

 superior portion of the volutions. The entire body-whorl 

 is sometimes (in the more aged examples, entirely) desti- 

 tute of the ordinary sculpture. The base of the shell, 

 which is not angulated at the circumference, nor compressed 

 below it, but rounded throughout, is never incised with 

 spiral striaj only, but if not smooth exhibits almost to its 



