SKELETO-TEOPHIC TISSUES AND COXAL GLANDS. 157 



glands. I have not been able to trace the connections of these 

 spaces and cannot assert definitely that they are not tubular, 

 but I am inclined to regard them as brought about by the 

 subdivision of an originally simple sac, the walls of which have 

 given rise to in -growing trabeculai which have more or less 

 completely united so as to divide the original simple lumen of 

 the gland into a number of compartments. 



The cells themselves (PI. XII, fig. 5, In, ip.) which line these 

 compartments are remarkable in the first place for their size 

 and for that of their nuclei. Their dimensions are shewn in 

 PI. XII. Secondly, they are remarkable for the great develop- 

 ment of a cortical layer cr, which is finely striated or rather 

 tubulated. 



This cortical layer is developed on the surface of the cells 

 turned away from the lumen of the gland, that is, on the sur- 

 face which is in relation to the lacuniferous connective tissue. 

 In sections which cut this surface of the cells (that is, tan- 

 gential to the cseca) as in fig. 2, PI. XII, they may appear each 

 surrounded by a ring of cortical striated substance owing to 

 the fact that the cortical matter dips in some parts between 

 neighbouring cells, though it never descends so far around the 

 cell as to reacli the inner surface of the protoplasm (that which 

 bounds the lumen of the glandular caeca). The protoplasm of 

 the cells beneath the highly refringent cortical layer, is very 

 delicate, transparent and with a few scattered coagula when 

 prepared in section. A coagulum is not unusually found within 

 the lumen of the glandular caeca (PI. XII, fig. 5, kc) and 

 whether normally or as the result of preparation, one finds 

 occasionally the large nuclei of the gland epithelium detached 

 from the cell-protoplasm and involved in this coagulum. 



11. StKUCTURE of the COXAL GLANDS OF MyGALE. 



The coxal glands of Mygale present the same general struc- 

 ture as those of Scorpio excepting that in them the central 

 core of medullary connective tissue does not occur. Instead 

 of a series of inter-csecal spaces with sparse lacunar connective 

 tissue, we find in Mygale the inter-csecal spaces completely 



