L. E. Robinson and J. Davidson 
251 
micleoli. The protoplasm is finely granular, but exhibits a distinct 
reticulation and shows no subdivision into individual cells. The lumen 
of each alveolus appears to be formed by a number of intercommunicating 
lacunae which occupy the centre of the alveolus. The ducts of the 
coxal glands exhibit precisely the same structure as the salivary gland.s. 
They are lined by a chitinous intima which is spirally thickened, and 
the outer epithelial sheath is identical in its appearance with that of 
the corresponding structure in tlie salivary glands. The main duct of 
the gland after receiving the efferent ducts of the alveoli, runs inwards 
and forwards to the interspace between the first and second coxae where 
it opens as has been described in Part I of this paper {Parasitology vi. 
pp. 33-34). Associated with the main duct of the coxal gland is a small 
saccular diverticulum with thick walls composed of a single layer of 
cylindrical cells. The diverticulum opens into the duct almost at the 
termination of the latter at the external orifice, but what its function 
may be, we are at a loss to explain. 
The function of the coxal glands is still uncertain. In his work on 
the anatomy of Ornithodorus savignyi, Christophers^ gives a short account 
of the extrusion of fluid from the coxal glands (p. 10), his remarks being 
based on information derived from Major Donovan, I.M.S. The fluid 
is discharged while the operation of feeding is in progress, and Chris¬ 
tophers states that the secretion is slightly alkaline and that it prevents 
the coagulation of blood. In the same memoir (p. 4.5) he briefly describes 
the structure and relations of these glands in 0. savignyi, from which 
it would appear that they are very similar to those of Argas persicus. 
Leishman^ appears to have been the first to demonstrate that the 
coxal fluid of 0. mouhata prevents the coagulation of the blood. 
Ktinssberg^ cites Christophers’ observations, and proved by actual 
experiment, that the secretion of the coxal glands of 0 . mouhata 
inhibited the coagulation of the blood of dogs and rabbits. She 
concluded that the function of the glands was the secretion of an anti- 
coagulin, and that it is analogous with the Funduszellen of the salivarw 
glands of Ixodes ricinus. 
If this conception of the function is the correct one, the fluid 
discharged during the operation of feeding into the space between the 
ventral surface of the tick and the body of the host, passes by capillary 
attraction, presumably, to the wound, where it mingles with the issuing 
blood, the mixed fluids then being ingested simultaneously by the tick. 
’ Christophers, S. E. (1906), pp. 10 and 4-5. 
- Cited by Nuttall and Strickland (1908), p. .310. ^ Kiinssberg, K. von (1911). 
17—2 
