No. 374.] REVIEWS OF RECENT LITERATURE. 135 
The general law-is suggested that when the main features of 
ornament are foreshadowed in the early nepionic or brephic stage, 
and especially when they obtain even in the protoconch, that orna- 
ment may be regarded as of value in the determination of species. 
On the contrary, when the ornament does not make its appearance 
until the late neanic or adolescent stage, and, even in an elementary 
sense, is not completed until what may be regarded, by analogy, 
as the early mature stage, that ornament merely characterizes 
the individual, and is only of negative use for the purposes of 
classification. 
As is well known, the size of the protoconch is variable, even in 
the offspring of a single individual, that difference being commonly 
attributed to carnivorous proclivities on the part of the larger speci- 
mens when in the embryonic stage. The author also notes that 
the size of the protoconch does not seem to have much influence in 
determining the size of the, shell in the adult. The larger proto- 
conch is not very often accompanied by the production of a larger 
adult shell than that which comes from a much smaller protoconch, 
that is, in the same species. There are, however, exceptions to 
this, and, correlatively, it may be noted that the shape of the proto- 
conch occasionally determines the general shape of the shell. 
Further interesting observations are made on the development of 
the Volutidae, the columellar plications in Mitra, and the recur- 
rence of a type of ornamentation in a species of Cerithium, All the 
genera are briefly described, and the type species is given. The 
notes on the species are preceded by a list of the synonymy and 
bibliographic references. 
Some changes in the nomenclature of the genera will not meet 
with general endorsement, although the principles adopted are, for 
the most part, those approved by the best authorities. Thus, the 
name Nuculana (Link, 1807) is used instead of Leda (Schum., 18 17) 
on the ground of priority. Nuculana, however, was given by Link 
as a mere verbal substitute for Nucula (Lam., 1799), as Dr. W. H.: 
Dall and others have shown. Link’s diagnosis applies to Nucula 
and not to Leda, for he says that the shell is “smooth, closed 
all round.” Nuculana (Link zon Adams) is therefore “an exact 
synonym” of Nucula, and cannot be sustained on the ground of 
priority. Consequently the family name Nuculanidz, Adams, cannot 
be retained for Ledide. C.E B 
