828 Dr. L. Orley on Hair-worms. 
The characters for distinguishing the species must be 
looked for in the form of the head and in the end of the tail, 
as well as in the lines crossing the whole length of the body, 
which are either wanting or appear single or double. The 
colour of the cuticula, as also the length of the body, are 
insufficient to determine the species, as, according to our 
knowledge, one and the same species may exhibit the most 
different tints and sizes. The form of the body is so similar 
that it is not available for the purpose of determination. 
1. Gordius fasciatus, Baird. (Pl. XVIII. fig. 1.) 
Gordius fasciatus, Baird, Proc. Zool. Soc. xxi. (1853) p. 21; id. Ann. 
& Mag. ‘Nat. Hist. ser. 2, xv. p. 72; Diesing, Revision d. Nem. 
p. 602; Villot, Monogr. d. Drag. p. 53. 
Length 28 centim.; breadth 1 millim. 
Anterior extremity as well as posterior of a very dark 
colour, almost black, and roughened with raised circular 
ridges, which extend for about 3 lines. Only one specimen 
(female). 
Hab. North America. 
2. Gordius fulgur, Baird. (Pl. XVIII. fig. 2.) 
Gordius fulgur, Baird, Ann. & Mag. Nat. Hist. ser. 3, vii. p. 229. 
This gigantic species was collected by Wallace, and named 
and briefly described by Baird. It is very interesting to me 
to have discovered several of this species in unnamed bottles 
from different localities, and moreover to have found the male, 
which was hitherto unknown to science. 
The belief that this worm is luminous is highly probable, 
its iridescent property proceeding from the crossing lines of 
the cuticle, which cause also a luminosity in Lumbricus and 
Piscicola. The people of Batchjan, moreover, call it the 
“ lightning-snake.”’ 
Female: length 100-160 centim. ; breadth 1—-1°5 millim. 
Male: length 40-70 centim.; breadth 1 millim. 
The body is of the same breadth throughout, somewhat 
flattened, with two dark lines running along the sides of its 
whole length. The free end of the head is thinner than the 
other extremity ; but both are rounded off; the postcephalic 
region is ringed, as in G. fasciatus. ‘The cuticle is very firm, 
and is marked by lines crossing one another, which are gene- 
rally set nearly at right angles. ‘The hinder extremity of the 
male has two lobate processes, swollen at their free ends, and 
nearly touching; the thickening in the region of the sexual 
aperture is conspicuous. ‘The males are much thinner and 
smaller than the females, and nearly quite flat. 
