REINHARDT ON 
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L A 
changed quite suddenly, their breadth now becomes much greater than their height, and at the 
same time they are very short, and it is these peculiarly formed caudal vertebrae that are inclosed 
in, and support the caudal fin. The vertebral spines, already very low in the last lumbar 
vertebrae, become still lower in the caudal vertebrae; we should say that a spine, properly 
so-called, can scarcely be pointed out further back than in the twelfth; but the vertebral 
arch itself still remains as a narrow osseous bridge, and does not quite disappear until in the 
fourteenth caudal vertebra. The so called processus articulares, (P. mamillares , Retz.), as two 
separate processes, are not retained farther backwards than the fifth caudal vertebra, then they 
dwindle down into a single knob, placed in the mesial line at the root of the vertebral spine. 
The transverse processes, properly so called, may already be said to have all but disappeared in 
the eighth caudal vertebra, but an indistinct rudiment of such a process may, however, still be 
traced in the two succeeding vertebrae. As something quite peculiar to the species here 
treated of, it ought to be particularly mentioned that the transverse processes of the caudal 
vertebrae are, from the very first, perforated by a hole near the root, through which the lateral 
branches of the great artery of the tail ascend, whereas in the nearest related dolphins (the genera 
Orca and Globiocephalus ), this hole does not appear until in the third, fourth, or even fifth caudal 
vertebrae, as in these forms, the arteries in question do not perforate the transverse processes of the 
foremost caudal vertebrae, but ascend behind them. The dolphin which, as regards this peculi¬ 
arity, comes nearest to the species here treated of, may, perhaps, be the narwhal, the osteology 
of which in other respects is very different from that of our dolphin; for in that animal we 
find the hole already in the transverse process of the second caudal vertebra; in all other 
dolphins with which I am acquainted, it does not appear until farther backwards in the caudal 
region than even in the Orcas and ca’ing-whales, sometimes not until the thirteenth or 
fifteenth caudal vertebra (as in a species of Lagenorltynchus). The chevron bones (haerna- 
pophyses) are sixteen in number ; the two foremost are quite open beneath, or, in other words: 
their lateral parts are not united together; they are, moreover, much smaller than the succeeding 
one, and somewhat asymmetrical; in the Middelfart dolphin, the third one also, indeed, still 
consists of two separate lateral parts, but it seems that these would in time have been united 
into an arch, and this union has already taken place in the Refsnaes dolphin, though this 
individual is not a little younger than the former. On the other hand, it is not very probable 
that the lateral parts of the two foremost haemapophyses ever grow together. 
As the pelvic bones were wanting in both the otherwise complete skeletons at my disposal 
l can state nothing about them, and thus it only remains to give some account of the pectoral 
fins. The woodcut in the following page, which, at one fifth of the natural size, represents the 
structure of the left pectoral fin with the scapula, of the Refsnaes dolphin, will give a sufficient 
idea of the form of the different bones, so that a more detailed description will scarcely be neces¬ 
sary, and it may, therefore, be enough to add some few observations. The scapula is, com¬ 
paratively speaking, as high as in the killers, and considerably higher than in the ca’ing-whale ; 
but what especially distinguishes it from that of the latter, is that the three ridges destined for the 
insertion of the muscles, which run down from the superior arched margin towards the articular 
cavity, on the outer surface of the scapula, and which in the ca’ing-whale are so extraordinarily 
high and prominent, are here very feeble ; the two foremost of them even scarcely distinguishable- 
Finally, it deserves to be mentioned, that the acromion and the spina scapula issuing from it, have 
l>een removed to the very foremost edge of the scapula, so that the so-called fossa supraspinata, 
