PROFESSOR OWEN ON THE MEGATHERIUM. 
759 
the same protective functions as it performs in the tail of other quadrupeds, we find 
it reduced to the same small area or vertical dimensions, and applied close to the 
centrum, and the difficulty disappears. As the hypapophyses usually coexist with 
and support the haemapophyses, when these are present in the tail of a reptile or 
mammal, they cannot be ‘ homologous’ in any sense, and the hypapophyses are only 
‘analogous’ when they happen to be perforated by the carotid arteries, as in the 
cervical vertebrae of some birds, or when they include the caudal artery and vein, as 
in the tail of Serpents. No one can confound the parapophyses or inferior transverse 
processes (Plate LII., fig. b2,p) with the hypapophyses (ib. Ji), who has observed them 
as they coexist in the cervical vertebrae of a Crocodile; and the hypapophyses are 
equally demonstrated to be distinct from the haemapophyses by the presence of both 
in the tail of the Myrmecophaga juhata (Plate LIIL, fig. 60, hy, Ji). 
Description of the Plates, 
In each figure the same processes are indicated by the same letters. 
m. Metapophysis. d. Diapophysis. 
a. Anapophysis. ’( p. Parapophysis. 
Zygapophysis. . : hy. Hypapoph 3 'sis. 
PLATE XLIV. 
Fig. 1. The three last dorsal and three first lumbar vertebrae of a Frenchman. Side 
view. 
Fig. 2. The three last dorsal, first and fourth lumbar vertebrae of the same, from the 
dorsal aspect. 
PLATE XLV. 
Fig. 3. The three last dorsal and four first lumbar vertebrae of the Brown Monkey 
{Macacus nemestrinus), from the side. 
Fig. 4. The tenth and eleventh dorsal vertebrae of the same, from the dorsal aspect. 
Fig. 5. The five last dorsal and first lumbar vertebrae of the Puma {Fells concolor). 
Side view. 
Fig. 6. The ninth dorsal vertebra of the same, from the dorsal aspect. 
Fig. 7- The eleventh dorsal vertebra of the same, from the same aspect. 
PLATE XLVI. 
Fig. 8. An oblique upper view of the tenth, eleventh and twelfth dorsal vertebrae, to 
show the distinctness of the metapophysis (m) from the zygapophysis (z) and 
the diapophysis (c?),and the gradual change of position of the metapophysis 
{Leptonyx serridens). 
5 e 2 
