24 TEXT-BOOK OF ENTOMOLOGY 



The internal genital organs of both sexes are paired, and extend 

 along the greater part of the trunk; in either sex they may be com- 

 pared to two long, slender, straight cords extending from the fourth 

 to the tenth pair of legs. The two oviducts do not unite before 

 reaching the sexual opening (Fig. 15, ovd). 



The male sexual organs are more complicated than the feminine. 

 The paired testicular tubes lie in trunk-segments 6 to 12, on each 

 side, and partly under the intestinal canal, communicating with 

 each other by a cross-anastomosis situated under the intestine, and 

 which, like the testes, is filled with sperm. Of the paired seminal 

 ducts (vas deferens) in trunk-segment 4, each unites again into 

 a thick tube, sending a blind tube forward into the third segment. 

 Under the place of union of the two vasa deferentia arise the paired 

 ductus ejaculatorii, which open beneath in the uterus masculinus. 

 The anterior blind ends of the vasa deferentia form a sort of small 

 paired vesiculae seminales in which a great quantity of ripe sperm 

 is stored. The uterus masculinus is in its structure homologous 

 with the evaginable penis of Pauropus, Polyxenus, and some diplo- 

 pods, and the sexual opening has without doubt become secondarily 

 unpaired. The sexual opening is rather long and is closed by two 

 longitudinal folds. " In several respects the male sexual organs of 

 Scolopendrella are like those of Pauropus; in the last-named form 

 we have indeed an unpaired testis, but also in Scolopendrella we 

 see the beginning of such a singleness; namely, the presence of an 

 anastomosis uniting the two tubes, their communication by means 

 of a transverse connecting canal and a glandular structure in the 

 epithelium forming them. The male sexual organs of Pauropus 

 differ only through a still greater complication." (Schmidt.) 



Scolopendrella in habits resembles chilopods, being found in 

 company with Geophilus burrowing deep in light sand under leaves, 

 or living at the surface of the ground under sticks or stones. It is 

 very agile in its movements, and is probably carnivorous. It was 

 considered by Haase to be eyeless, but the presence of two ocelli 

 has been demonstrated both by Grassi and by Schmidt. Whether 

 the pigment and corneous facet are present is not certain. The 

 embryology is entirely unknown (although Henshaw reports finding 

 a hexapodous young one), and it need not be said that a knowledge 

 of it is a very great desideratum. It is most probable that the 

 young is hexapodous, since the first pair of limbs are 4-jointed, 

 all the rest 5-jointed; while Newport, and also Byder, observed 

 specimens with nine, ten, eleven, and twelve pairs, and Wood- 

 Mason confirms their observations, "which prove that a pair of legs 



