160 Transactions. — Zoology. 



specimen contained only fifty vertebrae, which are made up of 

 seven cervical, twelve thoracic, eleven lumbar, and twenty 

 caudal, with only eight chevrons. Wall's Australian specimen 

 contains fifty-one vertebrae — seven cervical, fourteen thoracic, 

 nine lumbar, and twenty-one caudal — with thirteen chevrons ; 

 KrefiVs, fifty-five vertebrae — seven cervical, thirteen thoracic, 

 nine lumbar, and twenty-six caudal — with ten chevrons. In 

 Wall's specimen the 14th rib is represented in the figure as 

 quite a small nodule, entirely unconnected with the vertebral 

 column, and is only l^in. in length, in contrast to the 13th 

 rib, measuring Hi in. In Krefft's specimen, too, the last 

 (13th) rib is much smaller (4 in.) than the 12th (12 in.) on 

 the left side. 



In addition to the twelve pairs of long ribs, the measure- 

 ments of which are given below, I found amongst the debris 

 of the macerating-pan, which had been carefully preserved 

 by the taxidermist (Mr. Jennings, who took a very great 

 deal of trouble to preserve every piece of bone and cartilage), 

 a small bone, measuring liin. in length {i.e., 35 mm.) by 

 about fin. (9mm.) in greatest breadth: this appears to be 

 a 13th rib of the left side. One end of this small bone is 

 broader than the other, and appears to be the lower end. 

 One surface of this bone is flat, the other strongly convex, 

 and the general form agrees precisely with the shape of the 

 12th rib just below its curved region. Moreover, we found a 

 long piece of cartilage, 4 in. long, broader at one end and pointed 

 at the other, flattened and curved, which I believe to be the 

 unossified distal portion of the rib. The proximal cartilage 

 which may have connected this rib to the 13th thoracic ver- 

 tebra is, unfortunately, missing ; possibly the connection was 

 ligamentous. We found no corresponding bone for the right 

 side, but a short piece of cartilage, about 1 in. in length, 

 corresponding to the upper end of the aforementioned car- 

 tilage, indicating the possible existence of a 13th rib on 

 right side. There can be no doubt but that, except in a very 

 carefully macerated skeleton, this last rib would be overlooked, 

 and in skeletons found on shore there is little likelihood of its 

 being preserved. 



The figure given by Wall (who only found the ribs of right 

 side and the 1st left rib) is wrong, in that he places this 14th 

 rib in line with the lower end of the preceding one ; it 

 should be in line with the upper end, just where the curve 

 commences to descend. 



Van Beneden and Gervais, in the brief account (p. 515) 

 given of an incomplete skeleton from Japan, find thirteen 

 thoracic vertebrae, recognisable by articular facets for ribs, but 

 add " there may have been fourteen pairs of ribs, the last 

 being free." 



