Embryology of the Phalangiidse. 403 



towards the ventral surface, and opens into the urinary sac 

 (figs. 34, 35, and 50, cox, cox^). The hitter (figs. 33, 34, 35, 

 and 50 — //<S', 0. I/S) extends a hjng way backwards into the 

 abdomen, while in front it stretches beyond the point of 

 attachment of the third pair of legs ; with its anterior blind 

 end it closely adjoins the bow-shaped bend of the terminal 

 vesicle (fig. 50). Not far from its anterior end there issues 

 from the urinary sac a tolerably narrow duct, which passes 

 downwards and opens to the exterior between the coxa3 of 

 the third and fourth pairs of legs (Loman) (figs. 33, 50 — 

 0. US). It was impossible to examine the histological 

 structure of the terminal vesicle more closely, since this por- 

 tion of the gland was found to be in a rather bad state of 

 preservation in the preparations. The structure of the tube 

 (figs. 37, 38) did not exhibit any considerable deviations from 

 the ty])ical structure of coxal glands, as, for instance, it has 

 been described by Lankester and others in Scorpio, &c. Tiie 

 wall of the urinary sac (fig. 36, surface view) consists of a 

 memhrana propria with small and a pavement epithelium 

 with large nuclei ; muscle-fibres were not found in it. The 

 remainder of the chapter on the coxal glands is devoted to an 

 analysis of the papers upon the coxal ghinds of the Arachnids, 

 especially to a criticism of the views of Eisig*, according to 

 which the coxal glands are homologous not with the nephridia, 

 but with the set^-forming glands (" Borstendriisen ") of the 

 Annelids. I may sum up my own views as follows : — (a) the 

 coxal glands of Phalangium consist of three divisions — ter- 

 minal vesicle, tube, and urinary sac ; {h) the same divisions 

 are found in the antennary glands of the Crustacea!; (c) these 

 three divisions are homologous with the three portions of the 

 nephridium of Peripatus (and Annelids), with the funnel and 

 terminal vesicle (in Peripatus — in Annelids the adjoining 

 portion of the coelome), the tube^ and the expansion of the 

 latter at its distal end ; {d) the coxal glands of Limidus and 

 Arachnids, as well as the excretory organ of the Zoea of 

 Eryjyhia described by Lebedinski |, and the antennary and 

 shell-glands of the Crustacea are homologous with the nephridia 

 of Peripatus and Annelids ; (e) Eisig's hypothesis as to the 

 homology of the coxal glands of the Arachnids with the 



* Eisig, " Die Capitelliden," Fauna und Flora des Golfes von Neapel, 

 xvi. Monographie, 1887, i. p. 374 et seq. 



t The " uephro-peritoneal sac " of the Decapods according- to Weldon 

 (Weldou, " The Kenal Organs of certain Decapod Crustacea,'" Quart. 

 Journ. Micr. Sci. 1891, vol. xxxii.) probably corresponds to an extraor- 

 dinarily developed urinary sac. 



X Lebedinslii, '•' Entwicklung von Eryphia spinifrons," Zeitschrift der 

 Neui'ussischen Xaturf. Ges. in Odessa, Bd. xvi., 1889 (in Kussian). 



