252 Bulletin Atncrican Museinyi of Natural History. [Vol. XXVII, 



neck, very broad, anteroposteriorly shallow, convex head and sharply grooved 

 trochlea, which has sharp high keels and vertical internal and external malle- 

 olar faces. The inner and outer keels are subetiual. On the back surface 

 the ectal facet is sharply triangidar. Superiorly it is well sej^arated from the 

 dorsal continuation of the trochlea. The sustentacular facet is a large oval, 

 located nearer to the internal than to the external border of the neck. Below 

 the decurved ectal facet is a pit which occurs in Erinaceus and may possibly 

 represent the vestiges of an astragalar foramen. This foramen is also repre- 

 sented in certain plantigrade INIustelidse such as Mephitis, in which the 

 astragalus is somewhat similar to the Solrnodon type. In general, however, 

 the astragalus in Solenodon contrasts with the Mephitis type in that both the 

 trochlea and the head are shallower than in the latter, and the ectal facet is 

 triangular instead of (juadrangular. The astragalus of Microgale (Fig. 19, 

 C^, C^) like that of Solenodon has a broad trochlea, slender neck, transversely 

 convex head, triangular ectal facet and oval sustentacular; but the trochlear 

 keels are much less sharp and the inner keel is small and low, so that the 

 trochlea as a whole appears to make a sharper angle with the neck. In 

 Ericulus to judge from jMivart's figure (1871, pi. v, fig. 5) the disparity be- 

 tween the inner and outer crests of the trochlea is even more pronounced, 

 the inner one being very small. In Centetes also the inner crest is much 

 smaller than the outer and the Avhole trochlea is large, and gently concave. 

 The neck is very oblique. In Erinaceus the relative size of the trochlea 

 becomes greater, but the inner and outer crests are parallel. In this form 

 as in Solenodon the ectal facet is well separated from the dorsal prolongation 

 of the trochlea. 



The cuboid touches the astragalus. In Microgale it is separated from the 

 astragalus, possibly because the navicular in this form is deeper. The cal- 

 canemm, as in other plantigrade types, has a short tuber and a flat spreading 

 antero-inferior end. A large process (Fig. 19, x), on the inferior outer angle 

 of the astragalus, perhaps serving for the attachment of the tarso metatarsal 

 ligament, occurs in Solenodon, Centetes, Ericulus, Microgale, and is indicated 

 in Erinaceus. The calcaneum bears no facet for the fibula, Avhich as in 

 Centetidise articulates solely with the external malleolar surface of the 

 astragalus. 



Internal to the elongate entocuneiform (a primitive mammalian character) 

 is a long prc-Jiallucal sesamoid which articulates proximally with the internal 

 angle of the head of the astragalus. The mesocuneiform is short and cjuad- 

 rate, the ectocuneiform longer, the cuboid large and over twice as long as 

 it is broad. The cuboid overlaps the ectocuneiform. The evenly developed 

 digits call for no special note save that distally digits II, III and IV appear 

 subequal, III being slightly the longest, a frequent Inseetivore character. 



