In _M. europæus_ the metacarpal of the third digit is much constricted in the middle. The shaft of the ulna is straight. Except in these particulars and the relatively small size of the whole pectoral limb, the latter appears not to differ materially from that of _M. bidens_. As shown above, the first digit in _M. bidens_ consists of the metacarpal bone only, while in _M. europæus_ a phalange is also present. _Dimensions of the skeleton of the Atlantic City specimen of M. europæus, No. 23846, U.S.N.M._ mm. Length of the seven cervical vertebræ[a] 94 Length of first, second, and third cervical 45 vertebræ[a] Atlas: Greatest breadth 156 Greatest height 103 Height of neural canal 36 Greatest breadth across anterior articular 96 facets Axis, greatest breadth 144 Seventh cervical vertebra: Greatest breadth 80 Greatest height without inferior process 117 Greatest length of centrum 14 Greatest height of neural canal 49 First thoracic vertebra: Greatest height 151 Greatest breadth 136 Height of centrum 37 Length of centrum 21 Breadth of centrum (articular surface) 48 Height of neural spine 61 Height of neural canal 53 Seventh thoracic vertebra: Greatest height 246 Greatest breadth 116 Height of centrum 35 Length of centrum 69 Breadth of centrum 46 Breadth between transverse processes 66 Eighth thoracic vertebra: Greatest height 246 Greatest breadth (between transverse processes) 142 Height of centrum 39 Length of centrum 73 Breadth of centrum 47 First lumbar vertebra: Greatest height 263 Greatest breadth (between transverse processes) 215 Height of centrum (anterior) 43 Length of centrum 83 Breadth of centrum 53 First caudal vertebra: Greatest height 263