XVII.] INSECTIVORA. 291 



The Mole has an exceedingly long, narrow, and straight 

 pelvis, the innominate bones lying almost parallel with the 

 vertebral column. Both ilium and upper end of the 

 ischium are firmly ankylosed with the sacrum, leaving a 

 small sacro-sciatic foramen between them. Though the 

 pubic bones do not quite meet in the middle line below, 

 the brim of the pelvis is extremely contracted, and the 

 pelvic viscera pass below and external to the cavity instead 

 of through it. The pubes and ischia are very long and 

 straight, and inclose a large, but narrow, oval thyroid 

 foramen. 



In the Chiroptera, the pelvis is small and narrow ; the 

 ilia are rod-like, the pubes and ischia are not in a line with 

 them, but project forwards. The symphysis is often not 

 closed. There is usually a strongly developed " pectineal " 

 process, near the acetabular end of the anterior border of 

 the pubis, and which in some genera (e. g. Pliyllorhina, 

 Tricenops, Aseliia), is prolonged so far as to unite with a pro- 

 cess from the superior extremity of the ilium, inclosing an 

 oval foramen {preacetabular)^ as large as, or larger than, the 

 thyroid foramen. 



In many of the Rodentia, as the Beaver, the ilia are 

 markedly trihedral, with sides of nearly equal extent ; but 

 in the Hares, the outer (acetabular) border is almost obso- 

 lete, the gluteal and iliac surfaces are confluent, and both 

 face outwards, and the internal surface is largely deve- 

 loped above the sacral attachment. 



The pubes and ischia are always largely developed, flat, 

 and diverging posteriori}', the obturator foramen is of con- 

 siderable size, and the symphysis is long, and usually 

 becomes osseous ; in the Guinea Pig {Cavia), however, it 

 remains ligamentous, and the bones are widely separated 

 during parturition. 



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