86 GENERIC ALLIANCES. 
There are three shells belonging to different genera that appear 
“to converge to a point. The first is the Nassa (Aciculina) vittata, 
A. Ad., an almost smooth form ; the second is the Terebra (Kuryta) 
aciculata, Lam., smooth varieties; and the third is a Bullia from 
the Cape of Good Hope, having about the same proportions as the 
two previously-named shells, glossy and marked with bluish spots 
below the sutures. We have also specimens of the Columbella 
Menkeana, Reeve, from Australia, closely allied to the three elongated 
shells above-mentioned. Clark, in his ‘‘ Marine Testacea,” has 
placed both the genus Buccinum and Nassa in the genus Murex, 
from the resemblance the animals have to each other. ‘The Cyllene, 
Gray, is by no means distantly related to this genus (Nassa), the 
N. crassicostata, Marr., and the C. lyrata, Lam., are similar in colour, 
texture, ribbing, columella and thickened outer lip, the narrower 
and oblique form is all in which they differ. Planaxis is represented 
by a small shell described by Garrett under the name of N. 
anthracina, ‘‘ Proc. Acad. Nat. Sci., Philad., 1873.” The Cominella 
(Buccinuin) nassoides, Reeve, as its name implies, is closely related 
to the shells in this genus. Another genus, formerly included in 
Buccinum, the Truncaria, A. Ad. and Reeve, consists of shells allied 
to some of the varieties of Nasse. The N. varicifera, A. Ad., in 
its mature state, resembles both in cancellation and the varices 
shells in the sub-genus Rimella in Gladius=Rostellaria. ON. 
tritoniformis, Kiener, is allied to the Nassaria suturalis, A. Ad., 
° 
Singapore. 
Aw ILLUSTRATION OF ONE OF THE LINES OF DESCENT. 
THE varieties of the following shells meet at so many points, and 
intersect each other in such a variety of ways, that it appears to me 
quite useless to attempt to separate them into species. 
The fifty shells to which names have been given do not 
represent a quarter of the forms in my cabinet, nor could any 
conchologist determine the relationship existing between these 
specimens without first having seen the numerous unnamed and 
unfigured varieties by which they are connected. Very few 
