244 MEMOIRS OF THE CARNEGIE MUSEUM 
bone over this spot has largely disappeared, only a few flakes being adherent to the 
protruding mass of foreign matter. There is no depression at this point whatever, 
on the contrary there is an eminence. Both Mr. Hatcher and the writer were very 
skeptical as to the existence of a pineal or parietal foramen at this point, after we 
had carefully studied the original material upon which Professor Marsh based his 
description, and our skepticism was intensified by the study of the remarkably per- 
fect posterior portion of the skull in our possession, to which reference has already 
been frequently made. In the latter specimen there is absolutely no evidence 
whatever of a pineal foramen. ‘The two frontal bones unite by a.suture which can 
be traced backward to the point where the frontals articulate with the parietals. (See 
Plate XXVIII., Fig. 1.) There are no Wormian bones and no evidence of the thin- 
ning out of the skull at this point. In the specimen which has been restored by 
Mr. Hermann of the American Museum of Natural History, he has represented a 
large and conspicuous foramen as existing at this point. Quite a considerable por- 
tion of the margin of this foramen is artificial. In another specimen belonging to 
the American Museum of Natural History, a photograph of which has been kindly 
sent to the writer by Professor Osborn, and which is reproduced on Plate XXVIIL., 
Fig. 2, there is also shown an opening. A critical examination of this opening fails 
to disclose any true foraminal margins; on the contrary the edges examined micro- 
scopically show fractured surfaces. It is nevertheless quite possible that such an 
opening did exist in young and immature specimens and that it may have become 
closed up at a later period in the life of the individual. 
The occurrence of such an opening, which 1s doubtful, but which, did it occur, 
must have disappeared with increasing maturity, does not seem to the writer to 
furnish any support to the theory of the existence, at all events in Diplodocus, of 
such an organ as the so-called “ pineal eye.” 
Lesser Foramina of the Skull. —The beautifully preserved specimen (No. SY, 
Carnegie Museum Catalogue of Vertebrate Fossils) shows with remarkable clearness 
the location of many of the smaller foramina of the posterior portion of the skull. 
These openings the writer has diligently compared with the foramina in the skulls 
of recent reptilia and with the foramina found in the skulls of extinct reptilia, so 
far as they are known and have been interpreted. He is under special obligations 
in this connection to Dr. C. W. Andrews of the British Museum for giving him an 
opportunity to compare the material in his possession with a portion of the skull 
of Iguanodon bernissartensis which is preserved in the British Museum and of which 
Dr. Andrews has published an interesting account.* 
* Annals & Mag. Nat. Hist. (6th Ser.), Vol. XIX., p. 585. 
