392 SMITHSONIAN MISCELLANEOUS COLLECTIONS [vOL. 45 



The lumbar vertebrse (pi. xciii, i, 2) have transverse processes 

 peculiar to this genus. They are wide and long with the free ex- 

 tremity considerably expanded. The length of the longest process 

 equals the length of the centrum to which it is attached and half 

 the length of the centrum in front. The attached portion of the 

 transverse process arises abruptly from the anterior half of the side 

 of the centrum. The anapophyses are indicated by a mere ridge 

 or tubercle. Hypophyses are developed on the first three lumbars, 

 the first being the shortest and the third the longest. 



Except in absolute size the sacra in all the skeletons but one differ 

 in no respect from the sacra of the other genera. The single excep- 

 tion is No. 49,621, from the Jumna river, India. The narrow 

 posterior part of this sacrum is very narrow from side to side. The 

 expanded wing-like portion to which the ilia are attached is very 

 narrow. In general its shape, as seen from below, is like a T. The 

 adjacent edges of the first and third, and of the third and fourth 

 sacral neural processes are in contact. 



The total number of caudal vertebrse varies from thirteen to fifteen ; 

 of these the first is long and with a complete neural arch, the next 

 five or seven, usually seven, are of the form having more or less evi- 

 dent broad transverse processes, the remaining five to seven are small 

 rudimentary centra, without processes. 



Sternum and Ribs (pis. xciv, i, 2; xcv, 3, 4). — The sternum of 

 the genus Lepus is not very characteristic. The presternum is long 

 and narrow, compressed laterally into a keel, which is most prominent 

 anteriorly. The first rib articulates with it at the junction of the 

 first and second fourths, or first and second thirds. The mesoster- 

 num consists of four distinct segments, of which the first is narrow 

 and compressed, the remaining three are not compressed, and are 

 often flattened dorso-ventrally. All the mesosternal segments in 

 general are subequal in length, and each successive one grows wider. 

 The xiphisternum is about equal to the presternum in length ; its 

 anterior end is considerably enlarged where it articulates with the 

 last segment of the mesosternum. Its posterior free extremity is 

 rather pointed and only slightly larger than its narrowest portion. 



The form of the ribs is quite characteristic for the genus Lepus. 

 The spine-like portions of the tubercles of the ribs are well developed 

 and prominent. The eighth pair of ribs is the last pair bearing these 

 tubercles. The second, third, fourth, and fifth ribs are very flat and 

 broad on the ventral half of their shafts. The greatest width of one 

 of these ribs, just behind the spine and tubercles, is very much less 

 than the width of the shaft in its lower portion. Seven pairs of ribs 



