1888.] NATURAL SCIENCES OF PIIILADELPHIA. 89 



The Dorsal line of the Trunk. The Hue of the dorsal spines of the 

 Tertebral column (iucludiug the head as far as the parietal foramina/) 

 is one of the most instructive of these. The black line in the ass 

 and the horse has especially received the attention of Darwin. 

 Prof. Jno. Ryder'' detected a doi'sal arrangement of hairs in an 

 embryo of the domesticated cat. It retains the same color in many 

 carnivores. In the domestic cat two pairs of black stripes are often 

 found on either side. In domesticated cattle these are supplanted by 

 a white line. In piebald rats the stripe is commonly black. 



Lemur collaris,* has a prevalent squirrel gray color, while the head 

 is black and a black spot is seen at the root of the tail on the dorsal 

 surface. In Propithecus diadema,^ a conspicuous dorsal line is con- 

 tinuous with a black sacral region and tail. In Lemur varius^ the 

 same character of dorsal line is seen as in the foregoing animal but 

 is not so marked. In the parti-colored Lndris hrevlcaudatus' the 

 region of the back of the sacrum is distinguished from the rest of the 

 fur by being a uniform dull ochreous hue — a hue unlike that met 

 with in any other region of the body. In Propithecus verreauxi 

 coquerelii^ the dorsum near the lower part of the thorax is marked 

 by a dark spot, which is in contrast to the surrounding color. The 

 sacrum and loin are of a dirty gray color. In animals w^hich ex- 

 hibit spots on the line which are in contrast to the prevalent color 

 the retained colors may be looked upon as persistencies which for 

 some reason have resisted the forces which have displaced the line 

 itself. Such a view is in harmony with Darwin's statement* that 

 dappled and spotted animals were originally striped. One of the 

 numerous forms of Lemur varius exhibits a white circle at the base 

 of the tail the prevalent color being light brown. This does not of 

 necessity correlate with the dark sacral spot. But distinctive kinds 

 of marking at the root of the tail in the dog are of the same signifi- 



1 These are persistent in the human cranium near the sagittal suture a short 

 ^iistance in advance of the lamdoidal suture. 



2 Animals under Domestication pov. 



3 Proc. of Acad, of Nat. Sci. 1887, 56. 



* American Museum of Natural History at New York. 



5 Ibid. No. 263. 



6 Ibid. No. 266. 

 1 Ibid. No. 260. 

 8 Ibid. No. 973. 



3 Animals under domestication I. p. 6o.(Eng. Ed.) 



