256 A. FE. Verrili— Mollusca of the New England Coast. 
relatively shorter and broader and more regularly elliptical than the 
recent ones, as well as higher and more conical; they also have the 
aperture more central. In sculpture the two forms are very similar, 
but the fossil specimens have the sculpture decidedly coarser, with 
the radiating lines stouter, more elevated, and more unequal, one 
stronger rib alternating usually with three to five smaller ones, 
while in 4! Zanneri no such marked inequality exists. The apical 
pore and the internal callus are very similar in the two shells, but 
the pore is perhaps a little larger in the living form. A larger series 
of both the living and the fossil form might, however, show that 
they are both variable, and possibly grade into one another. 
Addisonia paradoxa Dall. 
Verrill, these Transactions, vol. v, p. 533, 
PLATE XXIX, FicuRES 10, 11, lla, 110. 
Mr. Dall has called my attention to the remarkable peculiarities in 
the structure of the animal of the male, which differs widely in 
appearance from the female (see our fig. 114), owing to the fact that 
the large verge is closely united at base with the right tentacle. 
Additional specimens were taken in 1882, living, at stations 1098, 
1109, 1110, 1124, in 89 to 640 fathoms; and in 1883, at station 2011, 
in 81 fathoms, off Chesapeake Bay. 
Choristes elegans, var. tenera Verrill. 
These Transactions, vol. v, p. 541, pl. 58, figs. 27, 27a. 
PLATE XXIX, FIGURES 9, 9a, 9D. 
This species was taken in 1882 at station 1096, in 317 fathoms; 
station 1124, in 640 fathoms; and 1154, in 193 fathoms (one dead). 
At station 1124 about twenty-five living specimens occurred in the 
empty egg-case of a skate (/taia sp.), in the same manner as those 
taken in 1881. They were associated with a limpet, Propilidium 
pertenue ? Jeftreys. 
Young specimens of various sizes occurred in these instances with 
the adults. Three of these young specimens are figured on our plate 
29. The youngest examples noticed consisted of about one and a 
half whorls; these are very small, white, regularly coiled, with the 
whorls well-rounded and increasing rapidly in size. The aperture is 
nearly round and somewhat oblique, with the lip perfectly continu- 
ous. The umbilicus is rather large and open and shows the previous 
whorls to the apex. 
