THE FCETUS. 195 



epidermis that becomes modified according to the wants of the sys- 

 tem. Far from being directed in front during this period, the eyes 

 are, on the contrary, turned very much to the sides of the head, as 

 is the case in a majority of quadrupeds. I have no need to say 

 that they are neither separated nor surrounded by any projecting 

 portion of the face, for the orbitar arches and root of the nose are 

 not as yet apparent. 



496. The ears. The ear also appears very early; it is distin- 

 guishable on the thirtieth day at the latest, and undergoes no re- 

 markable changes until the sixth or seven week; at first it looks 

 like the simple orifice of a cutaneous follicle, or a shallow and nar- 

 row pyramidal depression; some days later it might be mistaken at 

 a first glance for a leech bite, excepting that it has four angles in- 

 stead of only three. There is no trace nor rudiment of the auricula; 

 its opening is on a level with the skin, and like the eye, the organ 

 of hearing appears to be only a modification of a point on the tegu- 

 mentary surface; from the fifth to the sixth week the inner angles 

 of this crucial or rhoinboidal depression begin to rise above the level 

 of the skin; the tragus appears first, then the anti-tragus, and after 

 that the rest of the concha. All these parts grow by a sort of ex- 

 centric vegetation; and it is some time before they incline towards 

 the head, and dispose themselves in regular order. 



§. III. Of the ITfeinbers, and tower Parts of 

 the Trunk. 



I have in vain endeavored to learn which of the members appears 

 first. Whenever I have been able to distinguish the thoracic ap- 

 pendages; the pelvic extremities were equally visible. Neither have 

 I found in their dimensions such great disproportions as are men- 

 tioned by authors: at first there is only a small interval betwixt 

 them; the former emerge from the anterior part of the lateral bands 

 of the spinal trunk, at about an equal distance from the top of the 

 head and the point of the coccyx, supposing the embryo to be 

 straightened out; the latter are seen about one line above the coccyx, 

 which is curved from behind forwards, and concealed as it were in 

 the space between them. 



As long as none of the abdominal or thoracic organs are yet de- 

 veloped, they are not so near to the convex as to the concave sur- 

 face of the spinal circle; but the roots of them seem to be fartlier 

 backwards, as we pass farther and farther beyond the fourth week. 



The hand is seen first in the shape of a sort of pallet with a loose 

 and thin but undivided edge; the foot does not sensibly differ from 

 it; these two parts have a slightly concave surface, which is turned 



