Specimens of the two species of Indian hedgehogs (Paraechinus m. micropus and Hemiechinus auritus collaris) were collected from the vicinity of Pilani

formed by the fusion of the centra and the transverse processes of the four sacral vertebrae. The dorsal spines also show a tendency to fuse, leaving a narrow vertebral foramen. The sacrum articulates laterally with the anterior three-fourths of the iliac crest of the pelvis. The anterior broad, concave, mediodorsally directed superior articular facets articulate with the inferior articular facets of the fifth lumbar vertebra, and the posterior narrow end articulates with the first caudal vertebra. The anterior end of the first sacral vertebra is not horizontal, but is posteroventrally inclined at an angle of 67.50 with the dorsal long axis of the sacrum. This inclination of the centrum facilitates freer ventrad movement of the sacrum and the caudal vertebrae in rolling. Although the lateral articular surface is formed by the transverse processes of the four sacral vertebrae, the iliac crest articulates only with the first two and the anterior half of the third. On the dorsal and ventral surfaces are three sacral foramina on each side opening into the vertebral foramina. The transverse processes of the fourth sacral vertebra originate from the intercentrum and are homologous with the parapophyses. The posterior end of the sacrum is short. The vertebral foramen is narrow. The pedicle is short. The laminae are posteriorly directed. The inferior articular processes are small, convex and laterodorsally directed. The sacrum in Hemiechinus is composed of only three vertebrae as against four in Paraechinus. Another distinction is that the sacrum in the former is broader and stouter than that of the latter. Remarks.-Dobson (1882) described only three sacral vertebrae in Erinaceus (in all the 12 species recognized by him). According to him all three sacral vertebrae articulate with the iliac crest. Caudal vertebrae.-The caudal vertebrae in both genera (Fig. 1 B-D) range from 13 to 14 in number. The anterior three have fairly well-differentiated regions, the next four have only superior articular surfaces and the rest are cylindrical pieces representing the centra. There are no transverse processes in the last six or seven vertebrae, but the parapophyses are small anterolateral projections. The pedicle is much reduced or absent. The mediodorsally directed superior articular processes are well developed in the anterior vertebrae and originate from the anterior half of the body. The laminae are posteriorly directed and have at the distal end a pair of convex ventrolaterally directed inferior articular