516 



Bulletin American Museum of Natural History. [Vol. XXIV, 



Fig. 

 ossified larynx 



Solenodon paradoxus. 

 Nat. size. 



Hyoid bones and 



vacuity on each side of the basal third of the rostrum (see XXXI, Fig. 1), 

 but as such vacuities are absent in all other known skulls of Solenodon, 

 they are evidently abnormal or pathological. 



In correlation with the heavy ossification of the skull and the presence 

 of an ' os probocidis ' in S. paradoxus, the hyoid bones and all of the laryn- 

 gial cartilages are densely ossified (Fig. 9). 



The milk-dentition in Solenodon has been described and figured by 



I^esche, 1 on the basis of S. 



b /] 1 r ft cubanus, but his illustra- 



tions do not form a very 

 satisfactory basis for com- 

 parison, only a lateral view 

 of the teeth being given, 

 without any indication of 

 the maxillary-premaxillary 

 suture. The figures indicate slight differences in the form of the teeth from 

 what is seen in S. paradoxus. His descriptions are comparative with the 

 milk-dentition of the Centetidse, and are thus not definite and detailed. 



All the milk teeth of the upper mandible were present and in place except 

 the canine and dp 3 , which had fallen out by masceration, but were preserved. 

 The permanent tooth is visible at the bottom of the sockets, in each case. 

 The canine and dp 3 were, however, easily replaced, and are shown in situ 

 in Plate XXXII. The formula of the milk dentition is I , C t, P = 

 T = 14. Id 1 is not larger than id 2 or id 3 , but differs from them in shape, 

 being three-sided, with the inner face convex, and the longer diameter 

 transverse to the axis of the premaxillse. Pd 3 is slightly larger than pd 2 ; 

 both are conical, with a well developed cingulum. The maxillo-inter- 

 maxillary suture separates dp 3 and the canine. The canine is similar in 

 form to the adjoining incisor and slightly smaller; consequently many 

 times smaller than the permanent canine. Dp 1 is similar in form to p 1 

 and nearly as large ; dp 2 is about one half the size of p 2 and of similar form. 

 Also dp 3 has the same form as p 3 and is about two thirds as large. 



In the lower jaw id x and id 3 have the same form and nearly the same 

 size as ^ and i 3 ; but dp 2 is a small tooth, rather long, laterally flattened 

 and sharp-edged, but wholly lacks the inner groove so conspicuous in i 2 , 

 and is only about one tenth as large. Cd is very small a mere point, 

 while pdj is nearly as large as p x and of the same form; dp x has fallen out 

 and its successor protrudes above the alveolus; it has been preserved and 



_ i Enwicklungsgeschichte des Zahnsystems der Saugetiere, Part II, Heft 2, 1907, pp. 55, 56, 



