040 DR. J. W. DAWSOX OX E RRCT TRKKS COXTAIXIXG ANI.MAIi 



very laro'e and stout, nearly as long as the mandible ; let( hones and plialanf^es 

 correspond inyly stont. 



The thoracic plate is indicated only by some frajrments. The abdominal scales are 

 narrow and poiiited (oat-shaped), smooth externally and with a ridg'e at one side 

 within. 



The following- are dimensions of the largest specimen : — 



Length of mandible 4"4 centimetres. 



„ largest tontli f) millimetres. 



,, fennu' .■5'."> centimetres. 



,, til)ia "J ,, 



„ humerus 'J ,, 



„ radius 1 '5 



,, vertebra (> millimetres. 



,. rib 3 centimetres or more. 



„ scales 5 to 7 millimetres. 



Under the microscope the bone presents a coarser structure than that of Ili/hmoimis, 

 the bone-cells being large and of elongated form. The dentine of the teeth has coarse 

 tubes with canaliculi, the appearance being very similar to that in Siid/criK'toii, though 

 the tubes are scarcely so large. 



It seems evident that ILih'vprton Dairsoni was an animal somewhat stout and 

 broad in foini, with a large and [lointed head and massive limits. It seems to have fed 

 in part at least on Millijiedcs, as remains of these are found in eoprolite associated 

 with its bones. For some reason alsn, the s[iecimens of this species seem to have been 

 among the earliest introduced Into the erect trees, rerhajjs they sought their mvria- 

 podous food near these hollow trunks, or were in the hal)it of breaking up decayed 

 wood in search of Myriapods. 



7. IJi/JcriH'foii JoH;ii<l,'t,fn(i(tii, s.n. (Ph; e 42, figs. 8^ to 10!)). 

 [Preliminary Notice, American Jovu'nid of Science, Decembei", 1870. | 



Two specimens of the species occur in the collections, neither of them perfect. 

 Their characters warrant us in placing the animal in the genus Ili/li-r/x'toii. but it is veiy 

 distinct from the ])revious species, more especially in the length and slenderness of its 

 teeth, and in the breadth of its tliuiacic plate. 



Head nmch elongated, with the lioiies minutely pitted, and with delicate microscopic 

 stria^ but not .sculptured. Mandilnilar and maxillary teeth long and acute, pointing 

 backwards, with the apex of their inner sides finely striated ; twenty or more in each 

 ramus of the lower jaw ; palatal bones with several long slender teeth and many 



