SMITHSOXJAX MISCEIXANEOUS COLLECTIONS 



VOL. 95 



responds with that in species of Pycnogonida having eight pairs of 

 appendages, but not with the division Ijetween prosoma and opistho- 

 sonia in Arachnida, where the two parts of the Ijody are separated 

 between segments VI and VII. The genital openings, however, are 

 on the same somite, which is segment VIII, in both Xiphosurida and 

 .Vrachnida. 



Chl(l) 



Fig. 8. — Xiphosurida : body appendages and structure of the testes of Xipho- 

 sura Polyphemus. 



A, ventral view of body and appendages of young female, with carapace and 

 distal parts of legs removed. B, section of testis, showing testicular canals and 

 sperm sacs (from Benham, 1883). C, part of last, more enlarged (from Benham). 



Apds IX-XIII, gill-bearing appendages of opisthosoma ; Chi, chilarium ; Chi, 

 chelicera; I-XIII, postoral somites corresponding with appendages; 1L-4L, legs; 

 Lm, labrum; Mth, mouth; Opl, operculum; Pdp, pedipalp ; SpS, sperm sac: 

 TCnl, testicular canal: vO, ventral ocellus. 



The male gonads of XipJiosnra polyphenms, as described by Benham 

 (1883), consist of an intricate network of branching and reuniting 

 testicular canals (fig. 8 B, C, TCnl) spread through the entire upper 

 part of the body. The spermatocytes are developed in numerous 

 small follicular diverticula, or sperm sacs {SpS), opening from the 

 canals, and the mature spermatozoa are discharged through a pair 

 of short vasa deferentia (fig. 9 B, Vd), which open separately on the 

 genital papillae situated on the posterior (dorsal) surface of the base 



