GENERATIVE ORGANS OF AETHROPODA. 



■2 'J 'J 



The arrangements in the Pycnogonida are just as peculiar; their 

 generative products are formed on the wall of the coeloni, and are. 

 passed out by special orifices (which are sometimes found on all, and 

 sometimes on only one pair, of the feet). This character reminds us 

 of the lower arrangements seen in the Annulata. 



The conversion of appendages into copulatory organs, which 

 obtains in the Crustacea, is seen in the Aranea only from among 

 the Arachnida; in the males of this order the palpi are organs 

 of a complicated structure, which convey the sperm to the female 

 generative orifice. 



§ 232. 



The generative organs of the Myriapoda are, in their form 

 and arrangements, most similar to those of the Arachnida, and, 

 as in these forms, they sometimes open far forwards on the body, 

 namely, on the third segment of it. The genera- 

 tive organs of the Scolopendrida3 are placed in 

 the hinder end of the body. In the females the 

 generative glands are either simple externally and 

 form an elongated tube, on the inner surface of 

 which the ova form projections (Julidas, Scolopen- 

 dridse, and Glomeridas), or they are double (Cras- 

 pedosoma), in which case they are united at their 

 anterior ends, while the oviducts open separately. 

 In the Scolopendridas the simple ovarian tube 

 is, as a rule, continued on by a simple oviduct ; 

 but the double character of these organs is 

 implied in the development of ova on both sides 

 of the ovarian tube. 



The accessory organs are formed by two pairs 

 of bodies, which sometimes open into the ovi- 

 duct, but ordinarily directly into the genital 

 orifice; they partly form cement glands, and 

 partly receptacula seminis. 



The male organs also are often double in their efferent ducts and 

 accessory parts only. However, mauy Glomeridas and Julidas are 

 provided with a double testicular tube, which passes into a common 

 vas deferens, and seems to be united into a single organ owing to 

 the large number of its transverse connections (Fig. 157). When 

 there is only one testicular tube, it is beset with separate follicles. 

 The vas deferens is occasionally single (some Scolopendridas) ; but 

 as a rule it is divided into two branches, which either open on a 

 short papilla (Julida?, Glomeridse), or are connected together and 

 continued into a short penis placed at the hinder end of the body 

 (Scolopendridas). The last division of the efferent duct is provided 

 with enlai'gements or diverticula, which serve to collect the sperm. 

 Several pairs of glands are inserted into it just in front of its 

 orifice. As to the general character of the generative organs, they 

 are unmistakably approximated to the Crustacea by the possession 



Fig. 157. Male ge- 

 nerative organs of 

 Jul us. t Testicular 

 follicles, e Efferent 

 duct (after Steiu). 



