No. 2304. REPTILIAN CHARACTERS IN MAMMALS— WORTMAN. 



9^ 



foramenlike aperture or may be entirely wanting in Ptilocercus. 

 It is usually well developed in all the Primates, where it varies in 

 size from a large fenestra to a small foramen, or complete absence. 



That which is of the greatest interest in connection with this vacuity 

 in Tupaia is the occasional presence of a well-defined suture, in young 

 skulls, dividing the narrow rodlike upper boundary near its middle 

 and a suture separating its posterior boundary, just in advance of the 

 suture between the squamosal and jugal. This, it will be seen (fig. 4), 

 cuts off a separate more or less T-shaped bone, with the short stem form- 

 ing the upper back part of the boundary of the fenestra and two 

 prongs curved slightly upwards, one rising up to meet the postorbital 

 process from above and the other passing forwards on the upper 

 border of the fenestra tov/ards the lachrymal. Again in many young 



/"s/.J^ 



Pmx 



IPa. 



Fig. 4.— Tupaia. Ft., feontal; /. Fa., intekpaeietal; Ju., jugal; La., lacheymal; Na., nasal; Fa. 

 Paeietal; Fmt., peemaxillary; Ft. F., peefeontal; Pst. F., postfeontal; Pst. O., postoebitalj 

 Q. J., quadeatojugal; Quad., quadeate; Sq., squamosal. X 2. 



skulls there is what appears to be the remains of a suture running 

 forwards from the anterior border of the fenestra to the maxillary, 

 just below the lachrymo-malar articulation. In no case that I have 

 seen is this suture distinct and clearly defined, but the frequent 

 appearance of a line as if indicating the union of separate ossific 

 centers, points to the existence of separate pieces in the younger 

 stages of development. It may be said of all these sutures above 

 described that their presence is only occasionally indicated in skulls 

 young enough to show the main sutures, but, taken in connection with 

 what Vv^e shaU presently learn of the development of the human malar, 

 they assume an unusual importance and significance. 



What I take to be easily one of the most important of all these 

 newly discovered elements in the skull of the Insectivora is the 

 presence in Tupaia and other forms of a small though perfectly dis- 



