510 DR. J. MURIE ON THE ANATOMY OF THE SEA-LION. 
but short. The dorsal vertebre present no striking difference from those of Seals 
generally. Gradually narrowing, the dorsals merge into the lumbar vertebre, which 
are likewise larger, but not specially characterized from other Phocine genera. In 
computing the presence of four sacral vertebra, I am guided partly by the nervous dis- 
tribution and partly by the fact that the said number bears closest resemblance to each 
other of the series. Together they are distinguished by their raking neural arches and 
spines, subequal in length, and lying upon each other almost in an imbricated manner. 
The foremost has the largest body, the modified great flat-surfaced transverse processes 
forming a sacro-iliac synchondrosis, a facet of the second assisting. The bodies of the 
2nd, 3rd, and 4th are carinate, but, nevertheless, have not the depth of the Ist. The 
pedicles of their transverse processes are uncommonly squat, a retral bar, however, 
enclosing an intertransverse foramen. 
In our adult male animal under consideration, there are eight caudal vertebre re- 
markably movable upon each other by the intervention of thick interarticular fibro- 
cartilaginous disks. The vertebre diminish regularly from the first to the last, which 
is of very small size, and but incompletely ossified. The first two have each backwardly 
directed spinous processes. The third has two imperfectly formed thick laminar eleva- 
tions, but no spine. All three of these vertebre have well-developed transverse 
processes. From the fourth to the eighth caudal element there are no spinous or 
transverse processes, slightly raised elevation of the bone alone representing these 
structures. 
b. The Ribs.—Of the fifteen pairs of ribs, the 1st, 2nd, and 3rd are the shortest, then 
follows the 15th. From the 4th backwards to the 9th and 10th, there is a gradual 
increase in length, from which they decrease.as they go backwards. 
The subjoined Table gives the respective costal lengths in the young and adult 
animals. The measurements in each are from the angle to the costal tip :— 
Ribs. Young. Adult (Z.S. sp.). Ribs. Young. Adult (Z.S. sp.). 
USES SSBe once 15 27 Silence 65 10-0 
ZAIG Seon Neg ra 21 35 | LOU Ree tas 6-2 10-0 
SLUMS. de 3:2 5:2 eG ey ks te 6-2 9-9 
Athy sucyet- cts 4-1 6:8 Bothy ds ere 6-0 9-4 
Dili a scenr epi 4:7 78 TS th oy. sy ashe ‘ers 57 8°6 
Diemer: 5:3 8-9 AS cle Gisiarc 52 [Oo 
Tere oye esete 59 9-1 esting fey coher 39 6-1 
toldal) ve attri 61 9:5 
The first rib has a stout roundish straight body, with a very slight antero-posterior 
compression. ‘The neck, set almost at a right angle to the body of the rib, is thick, 
and markedly grooved in front and behind. The capitulum is of moderate size; it 
articulates with the anterior part of the body of the first dorsal vertebra, barely im- 
pinging against the intervertebral cartilage. The prominent tubercle, and its articular 
— 
ee ae ee ee 
