56 Proceedings of the Royal Physical Society. 



men figured in PL III., Fig. 1, anotlier and much smaller plate 

 (^:>. cl. I.) on each side, which has not previously been 

 noticed. It needs no reasoning to perceive at once that this 

 is the posterior dorso-lateral of Coccosteus (p. d. I., Fig. 3). 



It is curious that no undoubted remains of a ventral body- 

 carapace like that of Coccosteus have occurred in connection 

 with Homosteus ; but, at the same time, I might mention 

 that the plate ("Footprints," fig. 37) designated "palatal plate" 

 by Hugh Miller, looks to me as if it might well be the 

 anterior median ventral, so far as its shape is concerned, 

 though its great size may be considered as somewhat against 

 the supposition. At all events there is no evidence for 

 referring it to the palate. 



There are also several other bones figured by Hugh Miller, 

 and contained in the Edinburgh Museum, which, from the 

 way in which they occur, associated with other undoubted 

 remains of How.osteus, clearly belong to the same fish, but 

 whose position in the body I cannot speculate upon. These 

 are the "operculum" ("Footprints," 5th edition, fig. 39), the 

 very curious bone (ib., fig. 43) spoken of by Hugh Miller as 

 "shoulder {i.e., coracoid ?) plate;" his so-called "dermal 

 bones " (ib., fig. 44). What the bones c and e in fig. 46 of the 

 " Footprints " are, I am also unable to determine. 



But a number of the other remains figured in the " Foot- 

 prints " as " Aster olepis " belong not to Homosteus, but to 

 Glypitolepis paucidens, Ag., sp. These are the scales (figs. 26 

 and 27), the mandibles (figs. 32, 33, and 36), the sections of 

 teeth (figs. 34 and 35) ; the bone d (fig. 46), which I look 

 upon as the lower end of the clavicle ; and the interspinous 

 piece (fig. 48), which Hugh Miller figured as the " ischium 

 of Asterolepis." The latter is indeed a very curious bone, 

 and it is not at all remarkable that the author of the " Foot- 

 prints " should have sought to identify it with the basal 

 bone of a ventral fin constructed in teleostean fashion. 

 Knowing that such a pelvic fin-element could hardly have 

 existed in either Homosteus or Glyptolepis, the bone was long 

 a puzzle to me, until one day I observed a very similar bone 

 supporting the distal set of interspinous bones of the second 

 dorsal fin in a specimen of Glyptolepis leptopterus, also in the 



