„ ^ LAMELLIBKANCHIATA. 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-«, p, 611), It is evident 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 T. extenuatus shows a number of very small papillae 

 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. winchelU (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 mfeans of knowing whether they 

 appear in casts as merged into a single prominence or not. I. plicata, described but 

 not illustrated by Billings on p. 52 of the same catalogue, seems to agree much better 

 with Technophorus faheri, and it is not improbable that it should be referred to this 

 genus instead oi. Ischyrina.* 



* since the above was written and placed in the hands of the printer, 1 have had an opportunity, which I owe to the 

 Isindness of the officers of the Geological Survey of Canada, of studying the original types of Ischyrina winclwlli and /. plicate. 

 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 as in Technovhorus. The second species proves to be, as I suspected, a true Technophorus, with 

 close relations to T. su&ocufus and T. punctostriatus. Its surface markings are minutely puncto-striate, with about eight of 

 the finely pustulose concentric lines in 1 mm. 



