On the Parasphenoid of a Palcconiscoid. 421 



(fig. 6, S., A. P.). There are also three pairs of minute 

 postanal papilla} (A). 



1 have placed this species in the same genus as" the first- 

 described form, in spite of the peculiar structure of the 

 mouth-cavity, because in most respects the two are so closely 

 similar that I do not feel justified in separating them 

 generically. 



LIT. — A Note on the Parasphenoid of a Palceoniscoid. By 

 Henry Day, M.Sc, Geological Department, The Uni- 

 versity, Manchester. 



WHILST engaged in the determination of a number of fish- 

 remains collected by the late Mr. Binne\ of Manchester, and 

 labelled merely as" fish-remains," I came across two excellent 

 examples of the bone which has been called " parasphenoid " 

 by Traquair (i) speaking of Gonatodus, and similarly by 

 Fritsch (2) for Trissolepis, Sceletophorus, Amblypterus, and 

 Acrolepis. This particular bone of the fish cranium is very 

 rarely found, however, in any very complete state of pre- 

 servation ; in fact, the one found by Traquair in Gonatodus, 

 and described and figured by him (i, p. 16, pi. ii. fig. 5), 

 was the only one he encountered in his work on the 

 Pakeoniscidas. 



Traquair's example is apparently only moderately well 

 preserved, although he speaks of it as " a well-developed 

 parasphenoid/'' but Fritsch was more fortunate in finding 

 good examples in association with determinable fish-remains. 



In addition to the above two specimens from the Pendleton 

 Colliery, in the Binney collection, a third specimen came to 

 light in association with other fish-remains, from Ashton 

 Moss Colliery, and obviously incorrectly determined as 

 " Acanthodes." 



It is now proposed to describe these specimens in some 

 detail since they exhibit several very interesting features, 

 which throw light on the homology ot this element. 



All three specimens agree in general form and size with 

 Traquair's figured example, and would therefore in all 

 probability have belonged to fishes of about four or five 

 inches in length. 



Actual specific determination is difficult, but two of the 

 specimens are associated with other remains. One of the 

 Pendleton examples is associated with typical Pakeoniscoid 



