38 



fluent with each other, and with the remarkably thick and strong anterior 

 part of the vomer, are suddenly enlarged at their lateral margins, which 

 project in the form of rough oblong tuberosities into the nasal cavity. 

 The vomer expands superiorly into a horizontal plate, which supports the 

 thinner part of the nasal bones, and bends down at its outer margin, to 

 form the origin of the superior and anterior turbinated bones. A longi- 

 tudinal ridge extends along the inner or nasal surface of the superior 

 maxillary, to give attachment to the inferior turbinated bone ; the ante- 

 rior socket is in the form of a half- cylinder, with its convex side forwards ; 

 the second socket is an equilateral four-sided cavity ; the interspace be- 

 tween the anterior sockets is one inch and a half, and the narrow inter- 

 molar part of the palate contracts as it extends backwards. The inter- 

 maxillary bones have no ascending portion. They present a subcom- 

 pressed quadrilateral form ; their posterior extremities are wedged into 

 rough depressions of the maxillaries : they soon meet each other and 

 circumscribe the small anterior palatal foramina, which have a single in- 

 ferior outlet, and are firmly connected together by the whole of their 

 median margins : their anterior extremities, which are represented as 

 being expanded in the Madrid specimen, are broken off" in the present 

 one. 



This specimen was found in the bed of the River Salado, one of the 

 tributaries of the Rio Plata, situated to the south of the city of Buenos 

 Ayres. Presented by Sir JVoodbine Parish, K.H., Sfc. 8fc. 



"219. A portion of the middle part of the skull of the Megatherium, with a 

 vertical section removed from the series of teeth on the right side : these 

 are five in number, the last being the smallest, and with the convexity of 

 one of its curves turned backwards in a direction opposite to that of the 

 first molar. Besides their true number the teeth are shown by this sec- 

 tion to be implanted bv an undivided base, of nearly similar size and 

 form to the exposed crown, but excavated by a large conical pulp-cavity, 

 the apex of which extends to within an inch of the grinding surface of 

 the tooth. On the left side may be seen the malo-maxillary suture, with 

 part of the malar bone attached ; also the fronto-maxillary suture, and 



