132 NEW YORK STATE MUSEUM 



It represents a very large fish, perhaps the largest Eusthenopteron 

 ever found, measuring nearly three feet in length, and at the same 

 time shows nearly all the anatomical structures thus far made out in 

 this species. 



The accompanying figure gives a good idea of the specimen. The 

 fish is seen from the left side, and is so oriented that the paired fins 

 of both right and left sides are shov^n, while the caudal end is seen 

 in profile. An important fact to be deduced from the appear- 

 ance of the fossil is that Eusthenopteron was a more slender fish 

 than the current textbook restoration, which we owe to Whiteaves, 

 makes it appear. The depth of the fish in the region of the ventral 

 fins can be accurately measured in the specimen ; it is found to go 

 over seven times into the tOtal length (including tail). Hence the 

 ■niaximuni depth of the fish r ust have been contained six or six and 

 one-half times in the total len'^th, not four and two-thirds as in Whit- 

 eaves's restoration. In othe/ words, Eusthenopteron was shaped a 

 good deal like Tristichopterus, its nearest allied form. 



In the head region most of the cranial elements can be plainly 

 made out. The opercular elements are separated from the shoulder 

 girdle by a wide space, part of which no doubt represents the soft 

 membrane back of the operculum. The operculum (Op) and the 

 suboperculum (S. Op) are clearly shown. The large plate, P. Op, 

 probably comprises, as remarked by Traquair,^ both a preoper- 

 culum and one or more cheek-plates ; but the sutures separating these 

 parts can not be clearly made out. The cleithrum (CI) is broken off 

 at its lower end ; the piece I. CI, is probably the infra-clavicle broken 

 away from the cleithrum and shifted from its position. A gular 

 plate (G), that of the left side, is beautifully preserved. There is 

 no indication of lateral gulars in this specimen ; but it should be 

 recalled in this connection that Traquair found in a specimen in the 

 Edinburgh Museum '' the presence of five narrow lateral jugulars 

 [i. e. gulars] very distinctly shown." The mandible (Mnd) appar- 

 ently has sutures separating the dentary from one or more infra- 

 dentaries, but they can not be plainly made out. 



The fins are all present and are remarkable for the preservation 

 of their internal cartilaginous supports. Those of the pectorals agree 

 with the figure of these elements given by Woodward.^ The 

 ventral supports are not so well preserved ; one can make out, how- 



1 Traquair, R. H. Notes on the Devonian Fishes of Scanmenac Bay and 

 Campbelltown in Canada. Geol. Mag., Decade 3, VII, 1890, p. 15-22. 



2 Woodward, A. S. Outlines of Vertebrate Palaeontology. 1898, figure 23. 



