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MR. W, H. FLOWER ON THE OSTEOLOGY OF THE SPERM-WHALE. 
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Length of skull without rostrum . .| 14") 24" 34” | 57" 55" Db en DOL | 
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Prapeniont ent. 28.2 Lae. 100 100 | 100 | 100 | 100 100 | 100 
= | / | 
enethrotyostrumini.2 sc secs. I, 120 38 | 80 | 139 | 146 | 156 | 171 
Broporhionee ee | 143 | 158 | 235 | 244 | 265 | 279 | 305 
ixtreme breadth ~.2.<2..2..... 18 36 60 94 87 92 102 
IBroponblonecis ete cha retsyeuetclereiecs'6 128 «150-176 | «165 | 158 | 164 182 
Extreme height .............-. 15 | 26 | 44] 66 | 65 | 70 | 67 
eee =———— ae | 
WPnnrarbieny tech ns ses, sco 107 | 108 | 129 116 | 118 | 125 | 120 | 
| | 
Many of the differences of the skull, dependent upon age, are well illustrated in 
Pl. LVI., where drawings of median sections of the crania of the young and adult 
Tasmanian Cachalots are given on the same scale. Extraordinary as the disproportion 
of the facial part of the skull to the cerebral cavity appears in the older skull here 
figured, a drawing of the Yorkshire specimen would show the same character in an 
even more exaggerated degree. 
In the same Plate a figure of the section of the cranium of a Hyperoodon has been 
introduced, as that of the Whale which (except Hogia) approaches most nearly in its 
general characters to Physeter. It is easy to see, by this section, how those fantastic 
and apparently meaningless developments of the cranial bones of Hyperoodon and the 
Ziphioid Cetaceans may become, with little modification, the regular and definitely dis- 
posed walls of the huge spermaceti-basin of the Cachalot. The crest, essentially the 
same in both, is merely flattened out and expanded, as if by pressure from within; and 
the great maxillary protuberances are reduced in size. The most essential differences 
between the cranium of Physeter and the Ziphioids are, as already pointed out, the 
absence of a distinct lachrymal bone, and the construction of the zygomatic process of 
the malar. 
Lower Jaw. 
Perhaps no part of the skeleton of the Cachalot is so well known as the lower jaw, 
as few Museums of note do not possess one or more of these tangible trophies of a 
* Owing to the imperfect condition of this skull, the dimensions given cannot be relied on as quite accurate. 
