204 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



Diens of various ages, which are now preserved iu thecoUection of thelJiiited States Army Mediea! 

 Museum at WashiDgton. 



Cpon our return to Washington we searched the literature carefully for any statement that 

 would throw light upon the subject, but were unable to find that anything had been said or written 

 upon the subject other than the general statements contained in works upon human anatomy. 

 We accordingly prepared a paper setting forth the principal facts, which was presented to and 

 read before the Congress of Americanists held in Berlin. 



One of the chief difficulties with which we had to contend in discussing the general bearing 

 and importance of our discoveries was the lack of materials for comparison. Since then the writer 

 has been actively engaged in collecting materials illustrative of the characteristics of the hyoids 

 in the negroes and whites, and he is now in a position to discuss the subject upon a more accurate 

 basis. The sources of materials have been as follows : From Prof. ThomasD wight, of the Harvard 

 medical school, the Museum has received a record of 33 cases, of which 4 were black, 28 white, 

 and 1 of mixed Mexican and Indian parentage. These specimens were from individuals ranging 

 from 17 to 82 years of age, and include both sexes. From Prof. Towles, of the University of Vir- 

 ginia, the Museum has received 12 specimens of hyoid bones, all from negroes, with the ages 

 attached. From Prof. Matas, of the Tulane University, New Orleans, there are 17 specimens, of 

 which 12 are from negroes, 4 from whites, and 1 from a Chinese. From a personal collection there 

 are 23 specimens, of which 21 are of colored people and 2 are of whites. 



What may be considered as a typical hyoid arch of the higher mammalia is to be found in the 

 dog, Fig. 37, which is taken from Prof. Flower's " Osteology of the Mammalia." We prefer to follow 

 this author in the nomenclature of the several elements composing it, which 

 is essentially that proposed by Prof. Owen many years ago. In this we 

 observe first a central unpaired piece" or body, which is denominated the 

 "basihyal ;" from the outer extremities of this central piece two long slen- 

 der rods of bone project backwards over the upper edge of the thyroid car- 

 tilage and are called the "thyrohyals" or greater cornua. Near the junction 

 of the thyrohyals with the basihyal are attached the distal pieces of two 

 chains of bones which connect the basihyal iiiece or body with the temvioral 

 bones of the skull. The first piece of this series, counting from the basihyal, 

 is the lesser cornu or "ceratohyal"; the second is the "epihyal," the third 

 is the " stylohyal," and the last piece, which finally joins the skull, is that 

 called by Prof. Flower the " tympanohyal." 

 Fig 37._Extracramai por- ^j^-j^ ^^-g ^^j j^^ ^^^ ^.^^jj^.^^ ^j^^ typical arrangement of the mammalian 



tionofhyoulean apparatus of a " •' ' " 



fiofe', front view; «fe, stylohyal; hyoid apparatus, it so happens that in many forms, including monkeys and 

 eh, epihyal ; ck, ceratohyai uum the Complete bony connection between the basihyal and the base of 



(these three conatitute the ., , ,, , , . , - -i, ^ ii i • i, • , • j? i 



"anterior cornu"); bii, basi- the skull docs uot exist, owing Cither to the abscuce in this chain of bones 

 hyai, or "body" of hyoid; th, of ccrtaiu clemeuts or their rudimentary condition. In this case a ligament 

 nuJ" [leter FiovoT T" ""^ ™^y take the place of one or more of these elements, which in human anatomy 

 is known as the stylohyoid ligament. 

 Prof. Flower, in speaking of the liumau hyoid apparatus, says :* 

 The stylohyal, at first a long styliform piece of cartilage continuous with the tympanohy.al, commences to 

 ossify by a separate center before birth, and at a very variable period afterwards is often ( but by no means constantly) 

 ancbylosed with the tympauohyal and surrounding cranial bones, constituting the so-called "styloid process." This 

 is a condition not met with in any other mammal. Below the stylohyal the greater part of the anterior hyoid arch 

 is represented by a slender ligament (the "styloid" ligament), there being no ossification corresponding to the dog's 

 epihyal. 



This view has been generally accepted and it is now commonly taught that the epihyal element 

 of the dog is missing in the human hyoid arch. 



A difterent conclusion upon this important point has been reached by Thomas (de Tours), t 

 who, in speaking of the human hyoid arch, says: 



The body is the strongest piece of the entire apparatus. This is an osseous lamina curved in the form of an arc. 

 Its anterior face, very irregular, is convex from side to side and from above downwards, and is composed of two ob- 



• Osteology of the Mammalia, p. 159. t Elements d'ost^ologie, Paris, 1865, p. 219, PI. x. 



