THE GENITAL ORGANS. 



25 



riWA. C 



birth. This latter point was confirmed by Kowalevsky and Schulgin, 

 who observed the gland both in its earlier slightly coiled stage and 

 in its later more compact condition. [See Brauer, Xo. II.] 



The structure and position of the coxal glands in the youngest known s1 

 render it highly probable that they are formed from the somatic mesoderm. 

 They are assumed to be nephridia, a view which seems very probable. Considering 

 the primitive character 

 of the coelom in the 

 Scorpiones, we should 

 expect the nephridia to 

 open into the body- 

 cavity through funnels, 

 and this is actually the 

 case for a time. The 

 further development of 

 the inner terminations 

 of the gland must de- 

 pend essentially on the 

 modifications undergone 

 by the body-cavity, but 

 this point is somewhat 

 obscure. More thorough 

 ontogenetic researches are 

 required before it can be 

 stated with certainty 

 whether, as in Peripatus 

 and the Crustacea, a part 

 of the body-cavity forms 

 a capsule for the forma- 

 tion of the terminal sac 

 of the gland, or whether 

 the mouth of the funnel 

 is retained for a consider- 

 able time in a wide 

 secondary body - cavity. 

 The most recent writer 

 on this subject, Stukany 

 (No. 14) was not able 

 to prove that the coxal 

 glands in the Arachnida 

 opened into the body- 

 cavity, and he inclines to believe in the presence of a closed terminal sac, such 

 as is found in the Crustacea, but here also we must demand actual proofs. 



G. The Genital Organs. 

 The ontogeny of the genital organs has as yet been little investi- 

 gated. They were first observed by Laurie at a late stage of 

 development shortly before birth, in the first abdominal segment 

 [second, Brauer], as tubular structures at first unconnected with 



Fig. 14. — Euscorpius italicus. Portions of sections through a 

 newly-hatched Scorpion (A) and an advanced embryo (B) 

 to show the coxal gland and the formation of the genital 

 organs (after Laurie), a, efferent duct of the e<>xal gland ; 

 ec, ectoderm; g, efferent duct of the genital organ ; 

 genital operculum ; Ih, body-cavity; »t, external opening of 

 the coxal gland; mes, mesoderm; n, ventral nerve-cord; 

 Prs> Pti bases of the third and fourth limbs; SO, somatic, 

 sp, splanchnic layer of the mesoderm. 



