212 REINHARDT ON 



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 vertebræ that are inclosed 

 in, and support the caudal fin. The vertebral spines, already very low in the last lumbar 

 vertebræ, become still lower in the caudal vertebræ; 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 artkulares, {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 vertebræ. As something quite peculiar to the species here 

 treated of, it ought to be particularly mentioned that the transverse processes of the caudal 

 A-ertebræ 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 

 vertebræ, as in these forms, the arteries in question do not perforate the transverse processes of the 

 foremost caudal vertebræ, but ascend behind them. The dolphin which, as regards this peculi- 

 aritv, 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 

 reo-ion than even in the Orcas and ca'ing-whales, sometimes not until the thirteenth or 

 fifteenth caudal vertebra (as in a species of Lage7iorhymhus). The chevron bones (hæma- 

 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 Refsnæs 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 hæmapophyses ever grow together. 



As the pelvic bones were wanting in both the otherwise complete skeletons at ray disposal 

 I 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 Refsnæs dolphin, will give a sufficient 

 idea of the form of the diS'erent 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-w^hale ; 

 hut 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- 

 rinally, it deserves to be mentioned, that the acromion and the spina scapula issuing from it, have 

 been removed to the very foremost edge of the scapula, so that the so-called fossa supraspjinata, 



