ON DEVELOPMENT OF ATYEPHIRA COMPRESSA. 
395 
Among Decapods we find it in Eupagurus, Crangon, 
Panulirus, Atyephira, and so on. Mayer’s description of 
the ovary of Eupagurus corresponds with that of Atye- 
phira in almost every point Pf 3 ). In our common Crangon 
(probably C. vulgaris, Fabr.) the white band takes its peri- 
pheral position on the anterior half of the ovary, while pos- 
teriorly it penetrates into the interior of the ovary, and takes 
the axial course. In Panulirus japonicus, Gray, I have 
found it taking the axial course through the whole length of 
the ovarian tubes. 
Structure of the Ovarian Walls. — The wall of the 
ovarian tube consists of two sets of layers, the outer aud the 
inner, more or less separated from each other. The outer set 
is formed of (1) a connective-tissue layer, and (2) a super- 
ficial epithelium layer ; the inner consists of (1) a fine struc- 
tureless membrane, and (2) a layer of pyramidal epithelial cells. 
The outer connective-tissue layer (fig. 4) is formed of a thin 
matrix, embedded in which are seen fine, wavy, parallel lines, 
seemingly marked out into imperfect fibres, running in no one 
definite direction, but, on the whole, lengthwise. The nuclei 
of this layer (fig. 4, nc.) are very variable in sizes, measuring 
0‘013 — 001 mm. in length, and 0 - 006 — 001 mm. in breadth. 
Their forms are somewhat flat and elliptical. They have very 
delicate contour, and are provided generally with nucleoli, 
which appear as minute dots. We often recognise in this 
tissue the presence of pigment patches, whose form and size 
vary exceedingly. The colour of the pigment varies also from 
yellow to dark carmine. Clear spaces or lacunae of variable 
dimensions are generally to be seen intermixed with nuclei. 
This connective tissue can best be studied, as I have already 
said, in fresh specimens treated with very dilute acetic acid 
(•005 per cent.), and coloured with aniline or carmine, or else 
by simply colouring the freshly-taken ovary with Beale’s car- 
mine. By the former method the nuclei appear to be a little 
larger than they should, being (most probably) swelled up by 
the action of acetic acid. 
This connective-tissue layer extends all over the ovary and 
