WILLCOX: SYNONYMY OF THE ACMAEIDAE. 
219 
by Scutellina. Gray placed the new genus among the Patellidae; 
but H. and A. Adams, ’58, vol. 1, p. 460, included it among the 
Tecturidae. This appears to have been done on the strength of 
their own investigation; at least they give the earliest figure 
which I have been able to find of the animal as distinct from the 
shell, and mention, although they do not figure, the gill. /Scutellina 
retained its position in the Acmaeidae (= Tecturidae) either as a 
genus or as a subgenus (of Acmaea) until Dali, ’89, p. 410, after a 
careful study of the animal, transferred the genus from the Doco- 
glossa to the Rhipidoglossa, — a change which has been approved 
by Tryon and by Simroth. It is interesting to note that one of 
the points which decided Dali to make this transfer —the fact that 
the apex of the shell is posterior instead of anterior — was noted 
by Broderip in his original description. 
Although Scutellina has thus been removed by most authorities 
from the Acmaeidae, it is still occasionally included in that group. 
It may, therefore, be worth while to call attention to a brief paper 
by Pilsbry, 91, p. 88, in which he points out that Scutellina , having 
been employed in 1841 by Agassiz for a genus of echinoderms, is 
preoccupied, and must therefore fall as the name of a molluscan 
genus. He suggests as a substitute Phenacolepas . 
The Acmaeidae then include the following groups : — 
Acmaea Esclisclioltz — cervical gill, but no branchial cordon. 
Scurria Gray — cervical gill and continuous branchial cordon. 
Lottia Cpr. ex Gray — cervical gill and interrupted branchial 
cordon. 
If now we examine works dealing with the morphology of the 
family, we find these names often incorrectly used. I enumerate 
all the papers known to me which treat, otherwise than incidentally, 
the anatomy of any one of the Acmaeidae, noting errors of nomen¬ 
clature where I have found them. 
1. Rathke, ’33, gives a somewhat full description of the anatomy 
of Acmaea. 
2. Bouvier, ’87, j:>. 22, gives a brief account of the nervous sys¬ 
tem of Tectura (= Acmaea) testudinalis . 
3. Bernard, ’90, pp. 217-225, deals with two species of Tectura 
(= Acmaea) which are thus described (p. 217): “ C’est d’abord la 
Tectura (Acmaea ) pileopsis, qui differe des Patelles par la pre¬ 
sence d’une branchie bipectinee et la Tectura fontainesi , qui 
poss&de a la fois une branchie bipectinee et des lamelles branchiales 
circumpalleal es. ” 
