413 



and eighth dorsals, and rapidly elongate in the succeeding vertebrae, where they surpass in 

 length and equal in thickness the neural spines. They are much diminished in length in the 

 first sacral vertebra. Each of these elongated metapophyses presents a distinct articular 

 surface to an accessory posterior zygapophysis ; and on its opposite side an articular surface 

 to the subjacent anapophyses of the preceding vertebra, producing two additional pairs of 

 joints to the normal ones formed by the anterior and posterior zygapophyses. 



The parapophyses of the lumbar vertebra do not materially increase in length, but chiefly 

 in antero-posterior extent, overlapping each other, the back part of the anapophysis of the 

 last dorsal resting on the fore part of the parapophysis of the first lumbar vertebra, and the 

 parapophyses of the last lumbar vertebrae similarly articulating with a prominence of the iliac- 

 bone ; an additional pair of articulations being thus formed externally to those between the 

 anapophyses and metapophyses. 



The long sacrum has coalesced with both the iliac and ischial bones. The pubic bones 

 complete a wide arch by their confluence at their slender symphysis. The ischiatic notches 

 are converted into foramina, which are inferior in size to the foramina obturatoria. The 

 spines of most of the sacral vertebrae form by their confluence a continuous ridge. The 

 strong tuberosity of the ischium is bifid. The zygapophyses are developed and coarticulated 

 in the first five caudal vertebrae. The anterior ones support short and thick metapophyses, 

 and these are continued in the succeeding caudal vertebrae, after the anterior zvgapophyses 

 have disappeared. 



The haemal arch ceases upon the seventh caudal vertebra. Haemal arches are articulated 

 to the inferior interspace of the caudal vertebras, as far as that between the ninth and tenth. 

 The clavicles are complete. The scapulae are unusually convex externally, and present two 

 ridges or spines, the normal one of which is produced into a very long acromion : the coracoid 

 curves downwards : there is a well-marked tubercle behind the neck of the scapula. The 

 humerus is remarkable for its strength and for the great development of the deltoid ridges. 

 It is perforated above the inner condyle, but not between the condyles. The ulna is con- 

 siderably longer and stronger than the radius. The olecranon is remarkably developed. 

 The femur presents a long and strong third trochanter. The fibula approaches the tibia in 

 size, and is anchylosed to it at both extremities. 



Purchased. 



2291. The skull of the Weasel-headed Armadillo (Dasypm sexcinctus), with the 

 prominent part of the right frontal removed, exposing the rhinencephalic and 

 olfactory chambers. Presented by the Zoological Society of London. 



2292. The skull of the Dasypus sexcinctus vertically bisected. 



The petrosal presents a wide and shallow cerebellar fossa : the canal between the petrosal 

 and the angle of the superoccipital gives exit to a vein from the lateral sinus and an entrv to 

 an artery which emerges from the interior of the cranium between the petrosal and squamosal. 

 The rhinencephalic almost equals the epencephalic division of the cranial cavity in size. The 

 olfactory chamber extends backwards to beneath the prosencephalic division, and the eth- 



