PROFESSOR FLOWER ON THE RECENT ZIPHIOID WHALES. 229 
As noticed by Van Beneden' in Mesoplodon sowerbyi, the bases of the transverse 
processes of the hinder lumbar and caudal vertebre are not perforated by vertical 
vascular canals as in most Dolphins, but only the bodies of the posterior caudal vertebrae 
(beginning at the tenth) have such perforations. 
There are nine chevron bones. ‘The first consists of two pieces, not united in 
the middle line. The fourth is the largest. Their principal characteristic is that 
their spines are not particularly elongated downwards, but are large from before 
backwards. 4 
The Ribs.—Vhere are ten pairs of ribs, tolerably stout, especially thickening at their 
lower ends, though somewhat contracted rather above the middle. 
The first is short and broad, articulating above by a well-developed tubercle with the 
transverse process of the first thoracic vertebra, and by a short capitular process with 
the body of the seventh cervical. It has a strongly pronounced angle. 
The second to the sixth gradually increase in length, and diminish in thickness; 
afterwards they gradually become shorter. As far as the seventh inclusive, they have 
all distinct tubercles articulating with the transverse processes, and well-developed 
capitular process articulating with the hinder edge of the body or root of the arch of 
the vertebra in front. After the fourth the angle becomes obscure and is lost in the 
general convexity of the upper surface of the bone. In the eighth rib the tubercle is 
rudimentary, and does not reach the much diminished upper transverse process of the 
vertebra; the head articulates with the hinder edge of the base of the pedicle of the 
seventh vertebra, and on the right side only it has a small irregular articulation (not 
found in any other case) with the anterior edge of the pedicle of the arch of the eighth 
vertebra. 
The ninth rib wants the whole of that portion representing the head, neck, and 
tubercle of the ribs in front, and has a truncated upper extremity, articulating to the 
end of the large transverse process of the ninth thoracic vertebra. The tenth rib is 
similarly articulated with the corresponding process of the tenth vertebra, and is nearly 
as well developed as the one in front of it. 
The greatest length of each rib, in a straight line, is— 
inches. inches. inches. 
Burst Tee. S48. PSMA Pitt os fot see SOUL Weareelibiny eta. ated aver cheers 38 
Second jyactcremitelas DG ma SUSAN = ota ove oc aayaneests 39) aN ADEA ose oheysiopsel vei 32 
HUTT, Con sep cre 321 | Seventh............ SEP MIM UG Lie ommiScinpeDO 29 
Hourth. 7s 2 aL 37 
As in Physeter, Hyperoodon, and the other known Ziphioids, there are no ossified 
sternal ribs. 
The Sternwun.—The sternum (Pl. XX VII. fig. 3) is remarkably long and narrow. It 
1 Loe. cit. p. 42. 
212 
