512 APPENDIX. 
larger than one of the palpi. Each branchia unites with its 
fellow at the posterior dorsal extremity, and also in the 
middle of the dorsal line; it effects, on each side, a very 
slight junction with each pair of palpi. If that part of the 
branchial plate which is reflected back and fixed, were free, it 
would range and lap on its fellow portion, and thus constitute 
the normal pair of branchie. If this view is correct, we 
ought to consider the single plate as essentially a double one, 
though its component parts are abnormally arranged. The 
mantle is open on the ventral surface, with the margin irre- 
gularly scolloped. The liver is dark green. The ovarium at 
this season is studded with young, and occupies the entire 
surface of the body between the liver and the foot. 
At one time, from the character of the hinge, we were of 
opinion that Scrobicularia might have been associated with 
Syndosmya, but finding the branchiz and palpi of the two so 
very discordant, we abandoned that idea; we now think that 
the genus is superfluous, and that its smgle species may be 
transferred with great advantage to the same section of the 
Telline as T. solidula and T. tenuis, with which it agrees as 
to the soft parts almost precisely ; whilst in the hard parts it 
only differs in having a semi-internal cartilage, which with us 
is a point of little or no importance. 
PaNnvDoRA oBTUSA.—(P. 150.) 
Exmouth, July 1854. 
In our original account of this species, published in Forbes 
and Hanley’s Brit. Moll. vol. i. p. 211, we stated, that there 
were two palpi, one branchial lamina, and an obsolete one 
on each side the body; from subsequent observations we 
were induced to modify our opinion, thinking that there were 
two perfect branchial plates on each side. A further exami- 
nation of the animal has proved, however, that our original 
impression was substantially correct, as the following descrip- 
tion will show. 
The animal has two very short, reddish-brown, subtriangular 
palpi, blunt or rounded at their termination, which often 
