250 SCIENCE, 
other and bearson its inner end a prominent, 
slender, somewhat curved tooth, having a blunt, 
concave end ; in the opposite valve the hinge- 
margin is narrower, and the tooth, of similar 
form, is but little raised; a portion of the 
small, black or darker brown, external liga- 
ment, which separates the beaks and extends a 
little way on each side, passes between the 
valves and lies between these teeth, firmly at- 
tached to their concave ends. The dorsal mar- 
gin is further attached, by the extension of the 
thin epidermis, for a considerable distance both 
before and behind the beaks. 
The Tellimya Brown (1827) in its extended 
sense is synonymous with Montacuta Turton 
(1822). Brown divided his genus into three 
sections; the first included suborbicularis Mon- 
tagu (the type of Kellia Turton (1822)); the 
second included elliptica Brown and glabra 
Brown, both =ferruginosa (Montagu), (recog- 
nized as the type of Tellimya, taken in a re- 
stricted sense), bidentata (Mont.) and substriata 
(Mont.) (type of Montacuta given by Woodward, 
1851). Of the third section no examples were 
given. The hinge of this last species is care- 
fully described by Jeffreys (Br. C., II., p. 206, 
1863) as follows: ‘‘ Cartilage yellowish-brown 
and semicylindrical, clasping the hinge-line on 
the posterior side of the beaks; hinge-plate 
short and narrow but strong, not deeply exca- 
vated in the middle; teeth triangular and 
pointed, that on the anterior side in each valve 
being larger than the other; the teeth in one 
valve lock into sockets in the other, but not in 
the corresponding valve of every specimen, it 
apparently being indifferent whether the right 
or left valve contains the more prominent teeth 
or sockets.”’ 
H. and A. Adams (1858) separated the two 
genera, placing substriata as the only example 
of Montacuta and both bidentata and ferruginosa 
as examples of Tellimya, but the definitions 
give no distinguishing characters. Sars in 1878 
used Tellimya for ferruginosa (Mont.) and de- 
scribed and figured two new species, nivea and 
ovalis, and placed bidentata Mont., and substriata 
Mont., etc., under Montacuta. Professor Verrill 
also used Tellimya for the American form (per- 
compressa Dall), thought to be a variation of the 
English ferruginosa, and gave in Trans. Conn. 
[N. 8S. Von. X. No. 243. 
Acad., Vol. VI., p. 225, 1884, description and 
figures of the animal. The animal of the true 
ferruginosa was first described by J. Alder (Ann. 
Mag. Nat. Hist., p. 210, 1850). That Dr. Dall’s 
interpretation of Montacuta appears synony- 
mous with this is the probable reason for its 
not being used in his article. But that substri- 
ata and ferruginosa will prove generically re- 
lated needs careful consideration, especially as 
no external ligament has been mentioned as 
found in substriata, and only separate valves 
have been found of each of Dr. Dall’s new 
species. 
Jeffreys (Proc. Zool. Soc., London, p. 696, 
1881) proposed for the species described and 
figured by G. O. Sars as Tellimya ovalis the new 
name Decipula ovata; the new generic name, 
because Tellimya is a synonym of Montacuta ; 
the specific, because he disapproved of the 
meaning of ovalis. As Sars’ excellent figures 
show nothing that would generically separate 
ovalis from ferruginosa, Decipula becomes syn- 
onymous with Tellimya, but if the latter is dis- 
carded the former would have to be retained 
for this group. Jeffreys also made Sars’ sec- 
ond species, nivea, a variety of ferruginosa. 
[See also Monterosato, Bull. Soc. Mal. Italian, 
Vol. VI., pp. 57-8, 1880.] 
Montacuta planulata Stimpson (1851) was used 
by Professor Verrill in his Vineyard Sound Re- 
port (1874), but the great variations in size and 
relative thinness of texture in the American 
shells and their marked resemblances to a small 
series of English specimens led to the conclusion 
that in a larger series the same variations might 
be found and the English name bidentata was 
adopted. Dr. Dall finds that‘such variations do 
not exist, and again restores Stimpson’s name 
(p. 890). This is not the Lasea planulata Ver- 
rill (1879, Check-list) which is a large species of 
the same genus, measuring 8.5mm. in length 
and about 7.5mm. in height. It was dredged 
by the U. S. F. C. in Halifax harbor, in eight- 
een fathoms, 1877. It is thin, of delicate tex- 
ture, covered with a conspicuous dirty-brown 
epidermis; the hinge-teeth are unequal in 
length and strongly resemble the figure given 
by Dr. Dall, of Mysella Molleri (H6lbol) Morch, 
so that there is no doubt that it is the same 
species. 
| 
| 
| 
