LAMELLIBRANCHIATA. 613 
Technophorus.] 
Type: Technophorus faberi Miller. 
The shells included in this genus are in several respects very remarkable. This 
is true in the first place of their surface ornamentation in which they differ more or 
less decidedly from all known paleozoic representatives of the class, with the possible 
exception of Ischyrina Billings, a genus that will be discussed presently. As a sec- 
ond, though no less important peculiarity, we have the character of the beaks as 
these appear in casts of the interior. In all wholly known Lanellibranchiata, namely, 
the beaks of the two valves are distinguishable in casts as two more or less promi- 
nent points separated, as the case may be, by a narrow or wider depressed space 
originally occupied by the hinge plate. In casts of Technophorus, on the contrary, the 
fillings of the cavities of the two beaks forms a single pyramidal prominence. (See 
fig. 45-2, p.611). Itisevident then that immediately beneath the beaks, the hinge plate 
must be excavated, and a careful examination of the beaks of casts of T. extenuatus 
brought to light certain faint markings indicating that the excavation was occupied 
by either an internal cartilage or some peculiar type of muscle. The internal ribs 
are also unusually short and thick, and peculiar in this, that they meet in the center 
when the valves are closed so as to completely shut off the space occupied by the 
anterior adductor muscles from the cavity under the beaks. 
Unfortunately, the hinge proper is not shown by any of the specimens seen by 
me. Still, one of the casts of 7. extenuatus shows a number of very small papille 
along both the anterior and posterior sides of the hinge line that may have been 
produced by minute denticles on the hinge plate. But we cannot accept such uncer- 
tain evidence, so that for the present the hinge must be regarded as incompletely 
known. Ischyrina, Billings, so far as known to me from the description and figures 
of the type species, I. winchelli (Desc. Catal. Sil. Foss. Island Anticosti, p. 16; 1866) 
seems to be closely related to this genus. The internal ribs are better developed, the 
posterior one especially. Billings represents the latter as quite distinct from the 
hinge plate, which is not the case in Technophorus. There are posterior (Billings 
calls this side anterior) furrows and ridges, but the wing is very short. The beaks 
are stated to be small and obscure, but I have no means of knowing whether they 
appear in casts as merged into a single prominence or not. J. plicata, described but 
not illustrated by Billings on p. 52 of the same catalogue, seems to agree much better 
with Technophorus faberi, and it is not improbable that it should be referred to this 
genus instead of Ischyrina.* 
* Since the above was written and placed in the hands of the printer, 1 have had an opportunity, which Lowe to the 
kindness of the officers of the Geological Survey of Canada, of studying the original types of Ischyrina winchelli and I. plicata. 
In a cast of the interior of the first, the internal ribs are shown as represented by Billings. It shows further that the beaks 
are pressed down to the hinge and, though the impression is of one valve only, the evidence is fairly conclusive that the 
beaks were united in casts asin Technophorus. The second species proves to be, as I suspected, a true Technophorus, with 
close relations to 7’. subacutus and T. punctostriatus. Its surface markings are minutely puncto-striate, with about eight of 
the finely pustulose concentric lines in 1 mm, ‘a 
