68 
THE NAUTILUS. 
ness of Tryon’s figure, as above quoted, to other members of the 
genus ; moreover, the shell seemed familiar to me, and if I am 
right in my identification it is nothing more than the embryo of 
Fusus proboscidifertis, of which I have examples from Port Essing- 
ton. The apical whorls of that shell are often decollated, hut in 
some specimens there remains sufficient of the apex to permit one to 
arrive at the opinion just stated.” 
If any further evidence is needed to demonstrate the true nature 
of Perostylus, it is supplied by Mr. Edgar A. Smith of the British 
Museum (Natural History), who writes to me as follows: 
“The presence of a fine series of Fusus proboscidiferus Lamarck 
in the British Museum Collection, ranging from the very young 
state up to the adult form, enables me to show that Perostylus is 
merely the apical portion of the spire of that immense West and 
North Australian shell. 
“ The late Capt. Beckett brought from the Dampier Archipelago 
a number of specimens of this species besides a fine mass of the egg- 
capsules containing the young shells in large numbers. These 
agree exactly with the description and figure of P. brazieri (Tryon) 
and P. fordicmus Pilsbry, as given by the latter author. The num¬ 
ber of whorls in specimens from the same compartment of the 
mass of capsules is variable from four to six, and the length of 
the rostrum and canal is also subject to slight variation. Some 
specimens are also considerably broader than others. We have in 
the museum collection a specimen corresponding in size with Swain- 
son’s figure 1 of Fusus aruanus (—probocidiferus ) with the apical 
whorls still remaining intact. Another example is nine inches in 
length and still retains the nucleus, but in all the larger shells this 
part is broken off.’ 
“ The apical portion of Turbinella pyrum is also very similar, 
but a close examination reveals the incipient characteristic colu- 
mellar folds. 
“ In the description of Perostylus the apex is said to be decollated 
like that of Rumina or Cylindrella. Whether this is really the 
the case has yet to be proved by further observation. There cer¬ 
tainly is every appearance of there having been an embryonic shell 
which has become detached, but it is also certain that this takes 
Exotic Conchology. 
It is broken off in all the specimens in the Philadelphia collection.—P- 
