THE HUMAN SPECIES 



in tufts, but the tufts consist of coarse, matted hair, spirally 

 curled. 



A further distinction between man and the animals is the 

 absence of sinus hairs in man. In the lower animals these 

 hairs occur in the neighbourhood of the nostrils, on the lips and 

 throat, above the eyebrows and on the cheeks, and are dis- 

 tinguished by having large, ant-egg-like follicles penetrating to 

 the subcutis (see Fig. 54). Owing to the fact that the nature 

 of the pith of the hair is invariably characteristic of a species, 

 it is possible to distinguish between the hair of different animals 

 and between that of animals and man. In a human hair the 

 proportion of medullary substance to the whole hair is as 1:3-5 

 (see Fig. 50). 



The structure of the nails, both finger and toe nails, must 

 not be ignored as it forms a distinctive character of man, 

 especially as opposed to the apes. Among the semi-apes, 

 which, it is true, stand nearer the rodents and insectivora, the 

 thumb is furnished with a broad, flat nail, while the nail of the 

 index finger forms a claw, resembling 

 an awl in shape, and sometimes the 

 other fingers are also provided with 

 claws. The New World monkeys are 

 similarly provided, the thumbs of all 

 four hands being furnished with flat 

 nails and the other fingers with sharp 

 claws. With the exception of the gib- 

 bon, which has a broad flat nail on the 

 thumb and great toe, all the New 

 World platyrrhines, as well as the Old 

 World catarrhines, possess curved, claw- 

 like nails on all the fingers without ex- 

 ception. Careful observation shows us, 

 however, that also in man the nail of 

 the little finger at least is more arched than the rest. 



Various other structures exist in the human body closely 

 resembling those of the lower animals ; : among others may be 



1 Since the completion of the present work an interesting treatise has appeared : 

 Zur Morphologic und Anatomic der Halsanhange beim Menschen und bei den 

 Ungnlaten, by K. Frohner, Stuttgart, 1907. With 72 illustrations and n plates. 



FIG. 54. Sinus hairs of the 

 Norway rat. (Thome, 

 Zoologif.) 



