PREFACE. vil 
distinct species, because in one or two specimens certain head 
scales and the ventrals differed in shape and number. S. capensis 
is supposed to be distinguished by the “ frontal being a little 
shorter than the parietals ; two postoculars ; ventrals 203-241.” 
Simocephalus nyass@é is distinguished from the former by the 
“ Frontal being much shorter than the perietals ; a single posto- 
cular ; ventrals 171—-185.”’ 
I have found these characters are by no means constant. 
In some specimens the postoculars and frontal agree with S. 
capensis, while the number of ventrals agree with those of the 
other species, and visa versa. I have at this moment a specimen 
five feet two inches long before me, which has one postocular and 
210 ventrals. The frontal is very much shorter than the parietals. 
It will then be noticed that while the number of ventrals indicate 
that it is S. capensis, the other characters point to it being S. 
" nyasse. 
This volume is the outcome of many years of practical study 
of the snakes of South Africa, in their haunts, in captivity, and 
a long series of experiments with their venom. 
The majority of the illustrations are from direct photcgraphs 
of living snakes, and specially prepared anatomical preparations. 
If I should succeed in arousing an increased interest in this 
branch of Nature Study and in stimulating others to enlarge 
upon the knowledge collected, my object in writing this book 
will be fully attained. 
THE AUTHOR. 
Port Elizabeth Museum, 
Jan., 1912. 
