542 Dr. C. I. Forsyth Major on the 
O. hova this tooth is even somewhat more strongly developed 
than in that of the other two species. (The C. of Microgale 
is generally much feebler—fairly stout only in M. pusidla.) 
The tip of the C. of Oryzoryctes is recurved, more so in the 
lower than in the upper one. All the canines have a poste- 
rior basal cusp, which is more strongly developed in those of 
the upper jaw.—The upper Z. 1 converge towards each other 
and are provided with a strongly developed posterior basal 
cusp; J.2 has, as in the case of Microgale (cf. Leche, loc. 
cit.), an anterior and a posterior basal cusp, of which the 
former is still present even in the feebly developed J.2 of 
M. gracilis. J.3 is rudimentary, with indications of anterior 
and posterior basal cusps. Of the lower J. the middle one is 
the strongest, the hindmost the weakest and similar in form 
to J.3 sup. J.1 and J.2 are provided with a posterior basal 
cusp (I.d.2 appears to possess two). 
Thus we see—to recapitulate the morphological relations 
of the premolars, at least for the extremes of our series—that 
Pl, P. 2, and P.3. m\the upper jaw (47) 1) PA and, ie 
the lower) of Echinops correspond to M.2, M.1, and P.1 of 
Oryzoryctes hova in general form, and therefore without 
doubt in function also. Analogues of the two secodont teeth 
—P.2 and P.3 sup.—of O. hova are entirely wanting in 
Echinops. As has been mentioned above, the C.d. of Hehi- 
nops and Hriculus are still more premolariform than those of 
all other Centetidee which have here been discussed, while 
their /., in the permanent set at least, are not more compli- 
cated than those of Microgale and Oryzoryctes—rather the 
contrary. Up to acertain point, therefore, in the case of 
Echinops and Hriculus, C. and the posterior J, assume the 
functions exercised by the anterior premolars in the case of 
other genera. 
This condition partly coincides with that to which Leche 
has drawn attention and termed “release (Hntlastung) and 
reduction of the middle antemolars with simultaneous higher 
development of the anterior incisors ” *, which we now have 
briefly to discuss. 
According to Leche’s detailed account of this process +, 
the part played therein by the lower £.1 and C. is especially 
characteristic. ‘‘ The former,” he writes, “is reduced to the 
same extent as /.2 is developed, and it finally disappears 
altogether, so that in the lower jaw it is J. 2 that attains to 
the degree of development corresponding to that of the upper 
* Anat. Anzeiger, xiii. 1897, pp. 521, 522. 
+ “Zur Entwicklungsgeschichte des Zahnsystems der Siiugethiere &c. : 
I. Ontogenie,” Bibl. Zool. Heft 17, 1895, p. 39. 
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