GROWTH 01' EGGS AND EGG-STRINGS IN NEPHELIS. 199 



The ovaries are for the most part embedded in a soft con- 

 nective tissue, ill which many nucleolated nuclei {■0025 

 mm. in diameter) are to be ssen {n., lig. 4, PI. XVIi), but 

 no distinct cell outlines. 



The ovary-wall separated from this tissue has a thickness 

 of about '02 mm., and is composed of two distinct layers — 

 an internal layer of cells (/. ep., fig. 4) arranged loosely and 

 one cell deep, and an external layer {ea;., fig. 4) composed of 

 muscles and cells. 



In section the external layer is s,een to be by far the 

 thicker portion ; and it may, for sake of convenience, be 

 described as composed of four strata; although these, Avitli 

 the exception of the musculaa* strata, are not distinct. 

 These four strata, beginning with the outermost, are (1) the 

 circular muscle-fibres {dr., tigs. 3 and 4) ; (2) a stratum 

 composed of loosely-packed cells and a network of vaso- 

 fibrous tissue (Lankester) {o.f., fig. 3); (3) the semi-circular 

 muscle-fibres [s. dr., fig. o); and (4) a cellular stratum, 

 which differs from the second stratum only by the more or 

 less complete absence of vaso-fibrous tissue. The cells of 

 No. 2 and No. 4 really constitute one layer, being separated 

 only by the semi-circular muscle-fibres. 



The external stratum of circular muscle-fibres is seen in 

 surface in fig. 3, in longitudinal section in fig. 4, and in 

 transverse section in fig. 11. These fibres, varying in width, 

 but having a maximum of about '02 mm., have a transverse 

 direction, completely encircling the ovarial tube. They take 

 nearly parallel courses, except where they bifurcate or anas- 

 tomose, and never overlap one another. Thus their arrange- 

 ment forms a sort of network, the meshes of which are trans- 

 versely elongated. In transverse section they present 

 elongated elliptical figures, showing that they are flat 

 rather than round. Histologically speaking, they belong to 

 the unstriated class of muscle-fibres. The sarcolemma is 

 comparatively thick, and presents a homogeneous appear- 

 ance. The central portion consists of finely granular proto- 

 plasm, which encloses in widened places and at compara- 

 tively long intervals, large elliptical nuclei ('Oil x '007 

 mm.), in each of which a nucleolus is generally to be seen. 



In the superficial portion of the second stratum is found 

 a system of pigmented fibres, having a reticular arrange- 

 ment, as is shown in fig. 3, v.f. Although by far the greater 

 part of these fibres lie just beneath the circular muscle- 

 fibres, here and there branches are seen to penetrate deeper 

 into the wall. The larger fibres are evidently hollow, the 

 wall being formed of pigmented cells ; but others appear to 



