. 



Tacaaophorut.) 



Type: T'-<-hnithi>rus faberi Miller. 



The shells in.-lii.lfcl in this genus are in several respects very remarkable. This 

 i- true in the first place of their xirfaco ornamentation in which they differ more or 

 !<-- .Ifi-i'le.lly from all known paleozoic representatives of the class, with the possible 

 exception of l-,in/ri,i't Killings, a genus that will be discussed presently. As a see- 

 on. i. though no If-- important peculiarity, we have the character of the beaks as 

 these appear in casts of the interior. In all wholly known Lanellibninchiata, namely, 

 the Ke.ik- of the two valve- are <li-tinguishable in casts as two more or less promi- 

 nent points separated, as the case may be, by a narrow or wider depressed spare 

 originally oeenpie'l by the hinge plate. In casts of Ttchnophorus, on the contrary, the 

 tilling* of the cavities of the two beaks forms a single pyramidal prominence. (See 

 ti^r. !'-/". p. 61 1). It isevident then that immediately beneath the beaks, the hinge plate 

 must l>e excavated, and a careful examination of the beaks of casts of T. ertf nun tits 

 brought to light certain faint markings indicating that the excavation was occupied 

 by either a'n 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. extenuntus shows a number of very small papilla; 

 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, Hillings, so far as known to me from the description and figures 

 of the type species, /. winchelli (Desc. Catal. Sil. FOBS. 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 

 call- 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 caste as merged into a single prominence or not 7. plicaki, described but 

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

 with Technophorus /'//-./. an<l it is not improbable that it should be referred to this 

 genus instead of Ischyrinn* 



Slncr the abor* wu written and placed In the hand* of lit* printer. I bar* bad n opportunity, whlrb I ow to UM 

 kind MM of lira oem of UM OeoloftoaJ Surrey of Oaaada, of ( adyta* UM original typo, of bd*r*Mi *MMN aad 1. pMHta. 

 In a cut of tbo Interior of il- Int. the Internal rib* aw .bown w rvpmrnird by Bllllnc*. Il bo*, further U>mt UM b**k 

 an praiH down to ih bine* and. Ibough Ib* teprwloa I* of one lv* oaly. UM eld*w U fairly c..ola.lT, that UM 

 b*k were uni tl In raMa a* In TVefcuapfcnnn. Tne *wod pla provw to be. a* I oaparud. a tn> IMMopkonu 

 daw raUUooa to T. (MtaoiOu and T. iiHi*mlll*m, lu .urfam arklof* ar* miaul*)/ paaeto-MrUfo. wlib abaat l(bt of 

 UM tnlj paitalow eoaoMtrtc HUM In I mm. 



