4 DR. 1>. PELSENEER ON THE COXAL [Jail. 20, 



During the month of October 1884 a large living Mi/(/ale {Thera- 

 phosa), from South America, was placed by the Secretary of the 

 Zoological Society of London at the disposal of Prof. Lankester, 

 who had the kindness to entrust it to me in order that I might 

 make out the position of tlie coxal gland. He gave me at the same 

 time the series of transverse sections of the cephalothorax of Mygale 

 ccementaria, which he had made at an earlier date. 



Having carefully studied the latter, I drew those which passed 

 through the coxal gland, whenever this presented any change of 

 shape, size, or position. One of the sections in which the gland 

 presents its greatest development is shown in Plate II. fig. 1. 



By the help of this series of drawings I was able to construct two 

 diagrams, one of which showed the vertical projection (view from 

 the" side) of the gland, the other the horizontal projection (view 

 from above). The latler is shown in Plate II. fig. 2. 



In his recent paper ' Prof. Lankester expressed the expectation, 

 after examining sections of a South-American Ahjc/ale, that the coxal 

 gland was not a simple ovoid glandular body, as in Scorpio, but that 

 it vvas furnished with lobes corresponding to the coxae of the 

 cephalothojacic appendages, as in Limulus. The figure shows how 

 well founded this anticipation was. 



Taking these two diagrams as my guide, I looked for the coxal 

 gland of the large Mygale, which was still pretty fresh, as it had 

 only lain for a few days in GO per-cent. alcohol, having been opened 

 and washed with noimal salt solution (| per cent.) after being 

 killed, and I was able to dissect it out completely. 



The two glands, which are quite separate, are placed on each side 

 of the cephalothorax, at the side of the entosternite (enthodere of 

 Duges), between the lower plate and the upward prolongations of it, 

 to which latter they are intimately related in position, size, and 

 form ". 



Surrounded by the connective tissue with large brown cells, which 

 is found scattered through the entire body of Mygale^, they extend 

 as far as the edge of the lower plate of the entosternite, and have 

 four lobes which correspond to the projections of this plate and at 

 the same time to the four last appendages of the cephalothorax 

 (ambulatory legs) *. 



The anterior and posterior lobes of the gland are the largest, and 

 are parallel in direction to the long axis of the body. The second and 



section of Mygale javancnsis, Walk., given by Li6uard, "Eecherches snr la 

 structure de I'appareil digestif des Mygales et des Nepliiles," fig. 2 A (Bull. 

 Acad. Belg. 1878). The gland is shown under the upper part of the diverti- 

 ciduni of the stomach, between its bend and the entosternite. 



' Loc. cit. p. 52. 



^ The relations between the entosternite and the coxal glands are the .same in 

 Livmlus and Scorpio as in Mt/gule, as is easily seen from the works published 

 on this subject. 



^ This tissue is analogous to that observed in Scoipio by Prof. Lanke.ster 

 (loc. cit pi. xi. figs. 9-10), but the cells are larger, fewer in number, and 

 more scattered. 



* And not to the second, third, fourth, and fifth appendages, as in Limulus. 



