Royal Physical Society. 177 



years old, measures 14 lines (\% of an inch) round the largest 

 part of the head ; at the middle of the body, or about 4 inches 

 from the head, it measures 25 lines, and above the extreme 

 point of the tail it measures 5 lines. The head is ¥ V P art °f 

 the whole length — the body, including the head, being about 

 8, and the tail about 9 inches. These proportions produce 

 a form by no means repulsive, if the word elegant is objec- 

 tionable as regards a crawling thing. The animal is not, 

 therefore, " alike thick from neck to tail ;" nor does the tail 

 " end quite bluntly," according to stereotyped descriptions. 

 Young animals of the same, or of greater length, are more 

 slender ; those, for example, of the first year are from 13 to 

 14 inches long, although so slender as to bear the proportions 

 of a large earth-worm, the head and body being of nearly 

 equal diameter, and the tapering tail slightly smaller. A speci- 

 men of the fourth year, still of slender proportions, measures 17f 

 inches, and one of the seventh year bears nearly the same pro- 

 portions as the more aged animal before alluded to. After 

 the first year the growth is more to thickness, in proportion, 

 than to length. When observed carefully, the body seems 

 somewhat four- sided, and not strictly round — an aspect which 

 the colours of the different quarters tends to favour. 



2. Colour and External Markings. — The upper part (back) 

 of the head and body, in the mature animal, to the extent of 

 about a fourth of the diameter, is generally of a lustry yel- 

 lowish-brown marbling ; each side to the extent of one-fourth 

 is of a blackish chequered gray, in some instances more in- 

 tensely dark than in others, excepting on the sides of the head 

 and neck, which is a kind of mottling of lighter colour on a 

 dark ground, the remaining fourth, or belly, being of a bluish- 

 gray. In passing from the back to the head, there is a nar- 

 rowing of the lustry part, which again swells out anteriorly. 

 Two black spots mark the head — one commonly on each of the 

 larger vertical scales — and in the posterior spot there is an 

 opaque whitish point corresponding with a small opening in 

 the skull. A black zig-zag line passes down the back, di- 

 viding equally the bright yellowish-brown part from the 

 posterior central scale of the head to the point of the tail. In 

 some instances this line is more of a dovetailing character ; 



