in the Collection of the British Museum. 29 
Lycophidium Horstockii. Pl. VII. fig. A. 
I have mentioned, in ‘ Colubr. Snak.’ p. 197, that large spe- 
cimens about 2 feet long appear nearly uniformly black, a small 
number of scales on the posterior part of the body retaining 
bluish-white edges. 
We have received a very singular variety from the Gambia, 
through the kindness of Sir Andrew Smith: one of the speci- 
mens is 21 inches long, and the other about half that size. 
This is black, nearly all the scales having bluish-white edges. 
A series of thirty quadrangular white spots occupies the back of 
the trunk, each spot enclosing nine or ten scales. The series 
commences with a white longitudinal streak on the neck and 
occiput, and terminates with about seven streak-like spots on the 
back of the tail. 
This extraordinary variety might be taken as a distinct species; 
but there is not the slightest structural difference from the typical 
L. Horstocku. 
Aspidiotes melanocephalus, Krefft. 
Mr. Krefft has kindly sent to the British Museum a fine large 
specimen of this snake. I could not discover any teeth on the 
maxillary bone; so that Mr. Krefft appears to be justified at 
present in placing this snake among the Boide. However, 
there is in other points such a strong similarity to Liasis, that 
I cannot help thinking that an examination of younger examples 
of 2 or 3 feet in length may reveal the presence of those teeth. 
Atractaspis microlepidota. Pl. VII. fig. C. 
Uniform blackish brown. Body stout. Ventrals 212; sub- 
caudals simple, 26. Scales in twenty-nine series. Two pairs 
of frontal shields; one pre- and one postocular; six upper 
labials, the third and fourth entering the orbit; temporals 
rather numerous and irregular. 
This is probably a West African species. Our specimen is 
20 inches long, the tail measuring 18 lines. 
Atractaspis corpulentus. 
According to Hallowell’s notes (Proc. Acad. Nat. Se, Philad. 
1857, p. 70), his specimen had one pair of frontals and 182 
ventral shields; our specimen differs in having two pairs of 
frontals and 210 ventral shields. However, we have seen similar 
variations in one and the same species of African snakes, and 
would not regard the two specimens as specifically distinct, 
without further proof. 
The British Museum now possesses four very distinct species 
of this genus, so characteristic of the western and southern parts 
of Africa. 
