. Bulletin - United States National Museum. Science. A NEW WHALEBONE WHALE 35 The neural spine presumably was rather short, judging from its posterior location on the roof of the neural arch. This condition may be taken as an indication of the rapid diminution of the neural spines of the anterior caudals. The height (32 mm.) exceeds slightly twice the width (15 mm.) of the neural canal anteriorly. The massive centrum (pi. 14, fig. 8), which measures 162 mm. anteroposteriorly, is noticeably depressed or hollowed out above and below the transverse processes. The anterior boarder and extremity of
. Bulletin - United States National Museum. Science. A NEW WHALEBONE WHALE 35 The neural spine presumably was rather short, judging from its posterior location on the roof of the neural arch. This condition may be taken as an indication of the rapid diminution of the neural spines of the anterior caudals. The height (32 mm.) exceeds slightly twice the width (15 mm.) of the neural canal anteriorly. The massive centrum (pi. 14, fig. 8), which measures 162 mm. anteroposteriorly, is noticeably depressed or hollowed out above and below the transverse processes. The anterior boarder and extremity of the right transverse process (pi. 14, fig. 4) is missing and the left process is broken off" at the base. Both processes were broad at the base which occupies more than half the length of the centrum. On the four or five anterior caudals of some recent mysticetes the seg- mented blood vessels do not follow their upward course on the centrum in well defined grooves. On this Calvert caudal, however, these blood vessels obviously traversed a broad shallow groove which is directed obliquely upward and backward, commencing in front of the transverse process, to the posterior end of the neural canal. On the ventral surface of the centrum the anterior haemal tubercles although partially eroded are smaller and less protuberant than the large posterior pair which are also eroded. Medi- ally between these haemal tubercles is the broad shallow groove or haemal canal which transmits the caudal artery and caudal vein. Posterior Caudals: The four small terminal caudals (USNM 23059) were located posterior to the last caudal which has the neural canal inclosed by the neural arch. The smaller Calvert cetothere (USNM 16667) has six caudals of this type. The anterior end of the largest (pi. 15, fig. 1) of these four caudals is higher (117 mm.) than wide (106 mm.). The posterior end of the centrum is slightly convex and the anterior end is flattened. There is an obvious tendency in these pos
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