DINOTHEIUI'M. 



they tUto that the very rcmakable form and dispositions of the 

 binder part of the ukull show it to bare been connected with muscles 

 of extraordinary power to give that kind of inurement to the head 

 which would admit of the peculiar action of the tusks in digging into 

 and tearing up the earth. They furtW observe that my conjecture* 

 (p. 138) respecting the aquatic habits of thU animal ore confirmed by 

 approximation* in the form of the occipital bon to the occiput of 

 CWCM; the Di*oiktrium, in thia itnicture, affording a new and 

 important link between the Cciacta and the Pachyilcrinata." In. 

 Buokland. in this iccond edition, gives a copy of the profile of the 

 entire bead and of the restoration. 



Bettontion of IHnotherium gigantrum. 



ThU head has been exhibited at Paris, and seems to have excited 

 great interest among the French zoologist* ; for we find iu the 

 'Journal des Dlbata ' of the 21at of March in the year 1837 that at 

 the sitting of the Acade'mie Itoyale des Sciences de Paris on the day 

 before M. de Hlainville read a note detailing his particular views of 

 the position which the animal held in the animal series views which, 

 it is there stated, were adopted both by M. Dumc'ril and M. Isidore 

 Oeoffroy St. Hillaire. These views were detailed in ' L'Institut' of 

 the 22nd of March ; and the subject is so interesting that we here 

 present them to the reader, more especially as they are so much at 

 variance with the restoration, a copy of which is above given. 



" M. de Blainville read a note on the fossil head of the IHnotherium 

 gigmltvi* recently exhibited at Paris by Messrs. Kaup and Klipstein. 

 According to M. de Blainville the IHnotherium constituted a genus of 

 matnmifers of the family of the Dugougx and Lamantins, which family 

 makes a part of the order or of the degree of organisation named by the 

 last-mentioned zoologist Grarigradtt, on account of their heavy pro- 

 gression, and of which the first family is formed by the Elephants. 

 The following were the grounds stated for this opinion : 



"As regards the teeth, the molars, five in number on each side of 

 each jaw, hare their crown squared and deeply traversed by two 

 transverse elevations, the same as in the Lamantins. But as this cha- 

 racter occurs also in the Tapirs and Kangaroos, and even in the 

 Laphiodons, it would be far from sufficient for deciding the question, 

 if it were not joined with the absence of false molars and canines 

 (a formula which produces a considerable space between the first 

 molar and the incisors), and with the number and form of these last, 

 which entirely resemble small tuslu ; only they are implanted at the 

 extremity of the lower jaw and are directed downwards. Whether 

 or no there existed a pair of incisors in the upper jaw is an uncertain 

 point, the two extremities of this jaw which have been found being 

 more or less truncated. It may however be inferred, from the 

 enlarged and thick form of a fragment found some years ago, that it 

 is possible that the animal might have had upper incisors, but smaller 

 than those below : perhaps only rudimentary. 



" As to the form of the head and iU parts it corroborates what the 

 dental system bad established. In fact, the occipital condyles are 

 entirely terminal, or in the direction of the longitudinal axis of the 

 head, as in the Ionian tins and the Cetaceous Edentata, modified for 

 nistimrr in the water. The occipital surface is large, subvertical, 

 and even inclined from before backwards, with a profound mesial 

 depression, for the insertion either of a very strong cervical ligament, 

 or powerful muscles for the elevation of the head, and the besilary 

 part of the skull is narrow in its component parts ; while the synci- 

 pitofrontal region is on the contrary very Hat, very wide, as in the 

 lamantins and dugongs, overplumbing the temporal fossa, which is 

 extremely wide and extremely deep, indicating enormous levator 

 muscles for the lower jaw, not only for the purpose of mastication, 

 but adapted besides for the particular action of that jaw with its rake- 

 like incisor teeth. This disposition of the temporal fossa is perfectly 

 in harmony with the zygomatic arch, which is wide, thick, robust, 

 and complete, as far as may be inferred from the portion whioh it 



broken, but which nevertheless offers the articulating surface of the 

 corresponding bone, exactly as in the lamaiitins ; perhaps however 

 without the great enlargement which may be remarked at the jugal 

 appphysia of the temporal bone in the Utter. The orbit is, as iu the 

 animals last named, very small and lateral, but very largely open in 

 the zygomatic fossa. The auditor) 1 aperture is small, narrow, and 

 rather oblique from below upwards. The face is wide and lint- 

 prolonged and enlarged a little, as in the Cctacea, anteriorly. It 

 presents in its middle a very large aperture, the composition of which 

 it has not been possible to study on account of the position of the 

 head, which is upside-down, but which aperture, though evidently 

 wider and greater than that of the dugong, has evidently the greatest 

 analogy to what exists in that animal. The posterior orifice of the 

 nasal cavity is on the contrary very narrow. The sub-orbital hole is 

 very considerable, but even less perhaps than it is in the dugong. 

 With regard to the lower jaw, that again exhibits the greatest analogy 

 to that of the dugong, from the manner in which its branches are 

 curved downwards towards the anterior third part of their length ; 

 only, that of the JHnothtrium being armed at its recurved extremity 

 with a tusk, the ascending ramus offers, in its width and its comlyle, 

 which is as transverse as in the Carnirora, a concordant disposition : 

 so that the only motions permitted should be those of elevation and 

 depression, as in those animals. The ethmoid surface of the temporal 

 bone also is, as it were, a portion of a hollow transverse cylinder, 

 with an apophysary lamina, having an extremely strong ridge ' uno 

 lame apophysaire d'arrot extremement forte.' ' With this element 

 (says M. de Blainville) we may regard it as nearly beyond doubt that 

 the IHnotherium was an animal of the family of the Lamantins, or 

 Aquatic Grariyradtt, its proper position being at the head of tin: 

 family, preceding the Dugong, and consequently preceded by the 

 Tetracatilialuii, which ought to terminate the family of the Elephants. 

 In a word, the animal, in our opinion, was a Dugong with Tusk- 

 Incisors. We, must then suppose that it had only one pair of anterior 

 limbs, with five toes on each. As to the supposition that the animal 

 was provided with a trunk, which might be presumed from the great 

 nasal opening, the enlarged surfaces which surround it, and the size 

 of the suborbital nerve, as far as may be judged from the size of 

 the suborbital hole, we believe that this is at least doubtful, and 

 that it is more probable that these dispositions bear relation to a 

 considerable development of the upper lip and the necessary modifi- 

 cation of the uostrils in an aquatic animal, as is equally the case in 

 the dugong. We think even that the upper lip by its immense 

 development embraced the lower one, and thus hid even the base of 

 the tusks, and that the lower one was sufficiently small, as may be 

 presumed from the chin-holes (trous mentonniers). After this it is 

 easy to perceive that of the two principal opinions which have been 

 broached and discussed concerning this singular animal, we are much 

 further from considering it a great species of Eiieniata, near the 

 sloths, with Dr. Kaup, than from considering it as a tapir, asU. I'uvirr 

 did, from an examination of the molar teeth, the only parts then 

 known. In fact, there is, in our opinion, much less distance, in the 

 natural method, between a dugong and a tapir than between a dugoug 

 and a sloth.' In this note M. de Blainville has not taken into con- 

 sideration that the head of the Dinothtrium, as well an a phalanx 

 which was found in the same locality, are referred by Professor Knup 

 to the same animal ; but M. de Blainville does not believe that this 

 phalanx really belonged to the JHnotherium. ' In fact (says he), 

 Mr. Lartet found with these same phalanges a portion of a tooth, 

 which evidently indicates a great pangolin.' 



" At the end of the reading, M. Dumc'ril rose to confirm the views 

 of M. de Blainville. He insisted particularly on the transversal form 

 and great extent of the condyle of the lower jaw and of the articular 

 fossa destined to receive it. He much regretted the loss of the zygo- 

 matic arch, the bases of which only remain on the jugal and temporal 

 bones. ' The curvatures of this arch,' said he, ' would have given 

 ideas of the volume and force of the maaseter and temporal muscles, 

 which must have been considerable. It would be important to know 

 them to compare them with those of the Lamantin on one side, and 

 on the other with the Mryathcriiun, whoso skeleton is at Madrid. 

 Witli regard to the phalanges, which are believed to be those of 

 the Dinolhrrium, they are certainly analogous to those of the Sloths : 

 but in the Lamantin, the lingual phalanx, which is in fact a doublo 

 pulley with a mesial projection at the base, offers at its other extre- 

 mity a single point with a sort of hood (capuchon) below : that 

 is to say, inverse to that which is found in the great species of 

 Cats (Petit), and very different from those of the Sloths and the Ant- 

 Eaters.' " 



In this statement there is one position that is rather staggering ; 

 and indeed we cannot but think it probable that M. de Blainville has 

 not been quite accurately reported. He is made to observe that the 

 articulation of the lower jaw is such that the only motions permitted 

 should be those of elevation and depression, as in the Carnirora. 

 Now, that with true grinding teeth, like those of the /'./,,/,. ,:.,.,. )],,. 

 jaws should be limited to the motions of elevation and depress 

 admirably fitted for working the cutting edges of the scissor-tceth of 

 the Cctrm'roro, is almost inconceivable. Without venturing to give 

 any opinion as to the true position of this interesting genus in the 

 series, we may be permitted to observe that the evidence on 



