CRANIA FROM THE MOUNDS OF FLORIDA. 423 



( 8 ). The temporal fossa is of importance in determining the shape of the skull. 

 I venture to divide the crest answering to the limits of the temporal muscle impres- 

 sion into two parts, — the fronto-temporal and the parietotemporal. The fronto- 

 temporal part lies on the frontal bone, and extends from the end of the external 

 angular process to the stephanion. The parieto-temporal part lies on the parietal bone 

 and extends from the stephanion backward, curving down to or near the asterion. 

 In muscular individuals, particularly in males, both parts are well defined. The 

 fronto-parietal part is rugose and even spinose, when the other is faintly expres-sed. 

 Sometimes a sharp spicule of bone is directed downward. The crest is often abruptly 

 united with the parieto-temporal at the stephanion, — the beginning of the last-named 

 curve being high on the side of the cranium as though separated from the fronto- 

 temporal by a " fault," to use a term borrowed from geology. — The surface of the 

 posterior part of the temporal fossa exhibits a peculiar texture. The bone is smooth 

 and often porcellaneous. It is apt to be raised above the level of the lambcloidal 

 suture, which shows for a short distance from the asterion a serrated appearance 

 where the superior curved occipital line comes in contact with that region of the 

 human skull which is comparable to the occipital crest of the lower mammals. 

 The lambdoiclal suture as it approaches the asterion becomes harmonic in many 

 examples. The frequency with which this change is correlated with interruptions 

 between the frontal and temporal portions of the temporal crest is noted, and consti- 

 tutes an essential feature in the descriptions of skulls in this essay. The parieto- 

 temporal crest as it approaches the lambdoiclal suture is often defined by a Wor- 

 mian bone, thus suggesting in an interesting manner that these structures are 

 associated with the boundary lines of muscle-impressions. The Wormians appear 

 to represent the consequences of compensation in rates of growth of bones. They 

 are fines imposed by nature for neglect. I infer that these results of neglect may be 

 exemplified in aborted or delayed rates of growth of the more important elements. 



The squamosa and the so-called mastoid portion of the temporal bone (as seen in 

 articulation with the sphenoid, parietal and occipital bones), have been the subject 

 of special consideration. The pars squamosa is divided into the pre-squamosal and 

 the post-squamosal portions. 1 The pre-squamosal portion includes all of the temporal 

 bone which is seen in the norma lateralis in advance of the posterior border of the 

 auditory meatus. The post-squamosal portion is here reserved for that part of the 



process is present but in a rudimentary form and is exceeded in size by the tubercle answering to the 

 inner border of the glenoid cavity. The spinous process lies to the inner border of the tympanic bone. 

 The tegnien tympani is distinctly seen in the adult. A small opening in the position of the foramen 

 spinosum is evident, the foramen ovale being small and round. In Gorilla the parts are as in Anthropo- 

 pithecus ; the foramen spinosum, however, being larger. In Hylobates the parts are the same as in panto- 

 morphic forms in Man. The inner border of the glenoid cavity is without tubercle. The foramen 

 spinosum is evident. Thus Hylobates more closely resembles Man at the petrosal part of the guttural 

 region than does any other anthropoid ape. 



1 The author is not unmindful of Albrecht's proposition to divide the squamosa on the norma 

 basilaris into pre-tym panic and post-tympanic portions. The above division is thought to be preferable, 

 since the parts are of the sopiamosa alone,— thus being independent of other cranial elements, besides 

 which the parts directly over the tympanic bone remain by Albrecht's scheme unaccounted for. 



53 JOURN. A. N. S. PHILA.. VOL. X. 



