418 
AV. X. F. AVOODLAXD. 
of development of the maxillary gland in this larva is indi- 
cated in Text-fig. 2, a and which represents a reconstructed 
stereoscopic view of the gland based on a series of drawings, 
drawn to scale, taken from the serial sections. In this 
figure the gland is viewed from the dorsal aspect (cf. PI. 28, 
fig. 1, showing the adult gland). In a the three parts of the 
gland, which are now easily distinguishable, are shown in 
their correct relative positions. The end-sac {End S.) is 
shown to lie on the postero-dorsal aspect of, and in close 
apposition with, the kidney {M. Mx. GL), and the latter is, of 
course, continuous with the vertically descending duct (D. Mx. 
GL), the terminal part of which is not yet dilated to form a 
bladder. In b the end-sac ‘is supposed to have been pulled 
apart from the kidney in order to show the postei-ior position 
of the narrow canal [Com.) putting the two parts into com- 
munication. 
The Gr 1 a n d in a 14 mm. Larva, S q ii i 1 1 a s p . — 
Though the Erichthus larva of this size is not much larger 
than that of the preceding stage, and the maxillary glands of 
both stages are practically identical, yet the gland of the older 
larva differs in one small though important feature fi'om that 
of the younger. In a transverse section of the gland at this 
stage of development (Text-fig. 3) passing through the narrow 
communication {Com.) between the end-sac and the kidney, 
the cavities and walls of these two regions are well shown. 
The cells composing the wall of the cavity I’epresenting the 
kidney {Me.) are very similar to those found in the gland of 
the adult Squilla. They are regular in outline and stain 
deeply ; the cytoplasm is granular, and there is a well-defined 
striated border present {Str. B,). The quite different cells 
composing the wall of the end-sac {End. B. C.) are, on the 
other hand, very dissimilar to those of the fully formed gland. 
As sho^yn in the figure the faintly granular cytoplasm is 
drawn out at irregular intervals into tent-like projections 
(P. C.), which stretch across the intervening space (haemocoele) 
to the layer of squamous epithelium surrounding the whole 
gland. These projections are apparently found in connection 
