514 
G. L. GULLAND. 
The difference in sculpturing between the fifth and the second, 
third, and fourth limbs consist in the almost entire absence of 
the chitinous ridge in the three last, and in the fact that the 
distal furrows is in them nearly median in position, and the 
two distal lobes therefore more nearly equal in size. In the 
interior of the limb the furrows are represented by a thickening 
and slight ingrowth of the chitinous cuticle. It is worthy of 
note that in the adult the depression which exists at the base 
of the coxae of all the limbs is most marked at the base of the 
fifth. 
For a short distance from the opening the duct is lined by a 
continuation inwards of the chitinogenous cells of the integu- 
ment, and these have a cuticle (fig. 11) on their internal 
surface, the whole being enclosed by a basement membrane, to 
which the trabeculae of the connective tissue are attached. 
The chitinogenous cells soon pass into the proper epithelium 
of the gland, which is identical in structure through the whole 
course of the tube. It consists of a continuous layer of proto- 
plasm surrounding the lumen, in which in a transverse section 
the nuclei are placed somewhat irregularly, and in which the 
division into cells, as in the adult, is not evident (figs. 4 to 10). 
The cortical part of the protoplasm when highly magnified is 
seen to be striated radially in the same way as in the adult 
(fig. 10) ; the internal part of the protoplasm is granular, and 
in it the nuclei lie. A basement membrane encloses each 
tube, and, as in the adult, the intertubular connective tissue is 
slightly modified from the ordinary connective tissue, inas- 
much as the lacunae are smaller, and the relative amount of 
trabecular or skeletal substance therefore greater. 
The internal opening of the tube is on a level with the 
point where the coxa of the fifth limb is just beginning to 
appear in the sections (fig. 1 is at this point). The tube 
marked D in figs. 4 to 9 is derived, as seen in fig. 4, from 
tube C, and is ventrally placed alongside of, and external to, the 
primary tube A. Its ventral wall disappears, and for several 
sections its lumen is in free communication with 
the spaces in the connective tissue which lie be- 
