21 



" SIR : The specimen submitted to me is the intracranial cast of some species 

 of Placental Mammals. The cranium had been subject to the influences of the 

 atmosphere, etc., for a considerable period preceding the formation of the cast, 

 and therefore the cast reflects the sutural dislocations which occurred in conse- 

 quence. The base of the brain cast it is not advisable to attempt to expose, on 

 account of the treacherous nature of the material. The convolutions corre- 

 sponding to the internal aspect of the Os temporale\\a.vQ not been clearly demar- 

 cated by the bone surface. The two narrow eminences on it are casts of the 

 grooves of the middle meningeal arteries. The convolutions of the occipital 

 surface had been well marked, but somewhat obliterated through denudation, 

 etc. The important region bordering on each side of the median fissure, and 

 corresponding to the fronto-parietal suture, is unfortunately as good as de- 

 stroyed ; and with this destruction the key to the interpretation of the specimen 

 is lost. However, this much can be stated with absolute certainty, that the 

 frontal region is sufficiently well preserved to state that its convolutions do not 

 correspond to those of the brain of the tapir, rhinoceros, hippopotamus, ele- 

 phant, pig, horse, hyrax, manatus, or any ruminant or cetacean. 



" They also differ in important particulars from those of the Canidce, differ less 

 from those of the Felidce, still less from the Ursidce, although corresponding to none 

 of them. The outline of the cerebral cast is found in two living animals the 

 marine otter and the seal. But in the seal the gyri show the transverse inter- 

 rupting series of sulci, characteristic of extreme brachycephaly ; and it there- 

 fore cannot belong to any animal corresponding to the seal. 



" The sea otter's convolutional details are unknown to me, and I believe have 

 not yet been studied. I therefore content myself with stating that the outline 

 of this cast corresponds to the outline of the sea otter's cranium. 



" It would help us a great deal if we could decide the existence or non-exist- 

 ence of a bony tentorium. The sutures of this cranium, as far as I can recon- 

 struct them, ran as in the diagram. 



" We may state definitely that this was not an ursine, feline, or canine brain, 

 nor the. brain of any terrestrial viverrine. It is an open question between an 

 aquatic carnivore and an aquatic pachyderm ; and although not placing my con- 

 clusion on an exact basis, yet, in view of the general outline, the course of the 

 convolutions, and the course of the sutures, I incline to the former view. 



" It certainly corresponds to no known brain of a living creature. In one 

 point I was inclined to suspect it to be a pachyderm, namely, the decided assym- 

 metry of some of the sulci, but this, by itself, is not decisive." 



" DR. SPITZKA. 



"308 East I23d street." 



The interesting letter quoted in full above, contains as near 

 a determination of the character of the animal to which the 

 brain belonged, as the nature of the cast and the materials for 

 comparison would permit. In a later report, by means of 

 more complete comparative material, we hope to be able to 

 reach a more satisfactory conclusion. However, as Dr. 

 Spitzka writes, the general outline, the course of the convolutions, 

 and the line of the sutures offer strong presumptive evidence 



