NOTES ON THE ANATOMY OF SCORPIONS. 121 
Notes on the Anatomy of Scorpions. 
I.—External Sexual Characters. 
By 
Muliyil Narayanan, B.A. (Madras). 
From the Biological Laboratory, Presidency College, Madras. 
With Plate IX. 
Ir is stated in certain text-books that male Scorpions differ 
from the females in having broader chelz and a longer post- 
abdomen. Professor Bourne has pointed out to me that these 
characters are not, at any rate in the species which we have ex- 
amined, valid. The chele of the male are indeed, in the species 
Scorpio (Pandinus) fulvipes, which is common in Madras, 
narrower than those of the female. 
Professor Bourne has called my attention to the fact that 
there is, however, a constant and well-marked difference between 
the genital opercula in the two sexes, and at his suggestion I 
have made the following observations. 
The genital operculum is sometimes spoken of as “a small 
valve-like flap ” (Claus, ‘ Zoology,’ English edition),! sometimes 
as the “valves which cover the genital aperture” (Huxley, 
‘ Invertebrata’). Lankester has stated? that among many of 
“the points which it seems desirable to note in all cases, and 
to record by enlarged drawings . . . . is the chitinization 
of the genital operculum, whether in two quite separate plates, 
as in Brotheas, or in one imperfectly divided plate.” 
My observations show that the division of the genital oper- 
1 « Zwei Klappen” (Claus, ‘ Grundziige der Zoologie,’ 1880). 
2 « Transactions of the Zoological Society,’ vol. xi, part x, 1885, p. 381, 
