ANIMALS. | 199 
This is a regularly formed species, apparently identical with both the Amphidesma 
lunulata and Cypricardia bicarinata of Count Keyserling: the former species has the | 
same pre-umbonal lanceolate depression, approximating umbones, and obliquely trun- 
cated anterior side; and the latter, the same granulated exterior, dorsal slope defined 
by a faint angle running from the umbones to the posterio-ventral margin, and squared 
posterior extremity,—as those characteristic of A//orisma elegans. 
Besides the lanceolate depression in front of the umbones, there is another behind 
them, rather deep, and extending the full length of the hinge-margin (Pl. XVI, fig. 4) : 
neither exactly agree with what are usually termed /unelte and corselet; though it is 
evident, they are but modified forms of these characters. 
The granulated surface of this species has some resemblance to that of A/orisma 
gibbosa (Sanguinolaria id., J. de C. Sow., ‘Min. Conch.’ pl. 548, fig. 3), which, it may 
be observed, although an allied species, has the extremities more acuminated. The 
granules, it will be seen, by a reference to Pl. XVI, fig. 5, display a tendency to fall 
into an obliquely lmear arrangement. 
The characters of the muscular impressions are represented in fig. 3, Pl. XVI. The 
pallial sinus (c) is very oblique to the ventral margin, offering, in this respect, a striking 
contrast to that of Al/orisma sulcata (Pl. XX, fig.5,¢c). The anterior adductor muscular 
impression (a), which is represented a little too high, has its lower border nearly 
horizontal with the posterior angle of the pallial line. 
Allorisma elegans occurs in the Shell-limestone at Humbleton Hill, and in the lowest 
beds at Whitley Quarry, where it is rare. Dr. Geinitz records its occurrence in the 
under Zechstein of Thieschtitz near Gera, and Corbusen near Ronneburg. The so- 
called Amphidesma lunulata was found in Permian Marl on the Uchta, a tributary of 
the Wymm, by Count Keyserling, who also discovered, in the same place, the so-called 
_ Cypricardia hicarinata, which is further recorded as being found in the Permian Lime- 
stone on the Wel near Kischerma. 
Py 
Family PSAMMOBIIDE (partum), Fleming, 1828. 
Dr. Fleming made the following genus typical of the present family,—a receptacle 
in which he also placed Asfarte. Having made the latter typical of a distinct family, 
it is herein excluded from Psammobiide, which, perhaps, embraces most of the genera 
subsequently grouped together by Mr. J. E. Gray and others under the name of 
Telmde. 
Genus Psammobia, Lamarck. 
Diagnosis.—* Shell transversely oblong, equivalve, subinequilateral, slightly gaping 
at the extremities; surface smooth, or transversely, and more or less radiatingly 
