VENOMS IN THE ANIMAL SERIES 295 
secreting cells, which are elongate, pressed one against the other, 
and supported at the base by a highly vascular substratum of 
connective tissue. The venom flows out between the layer of cells 
and the ensheathing membrane, which is capable of being pushed 
Fig. 105.—Pterois artemata (East Coast of Africa, Indian and Tropical Pacific Oceans), 
(After Savtschenko.) 
slightly back as the result of the penetration of the spine into the 
tissues, and then exerts pressure upon the reservoir. The latter is 
formed by the distension of the sheath under the pressure of the 
secreted liquid. 
There are twelve pairs of dorsal and three pairs of anal glands. 
