1881.] NATURAL SCIENCES OP PHILADELPHIA. 83 



fourth Ijody segment. (The first condition occurs in immature 

 specimens with less than twelve pairs of legs, the last in adults). 

 '• Genital orifice orf the ventral side of the body opening on the 

 third or fourth body-segment in both sexes. In one sex the open- 

 ing is a simple pore, in the other a longitudinal cleft, closed b}^ 

 means of an oblong chitinous piece on either side, the two together 

 occupying a sub-quadrate space. Heart dorsal ; traclieal sj'stem 

 lepresented by a series of simple tubular arches, without a spiral 

 filament, wliich arise from openings on tlie ventral surface of the 

 animal, inside the bases of the legs, widening and passing upwards 

 to and apparently in close relation with the dorsal vessel. Intes- 

 tine straight, with two ver}^ long, tortuous Malpighian tubules 

 opening into it at the posterior third (S. notacantha).^^ 



The main points of disagreement are in regard to the position 

 of the genital organs and the supposed tracheal arches. Menge 

 states that the oviduct opens posteriorly and above- the anus, and 

 claims to have seen the eggs in the latter and the ovary. As to 

 this point, I did not confirm his observations, although I do not 

 deny that he may have seen real ova. Nor do I now affirm posi- 

 tively that the ventral opening seen b}' me is genital ; the only 

 evidence being the circumstance that I found two kinds in different 

 individuals. Its function maj' be that of the ventral sucker of 

 CoUemhola. Menge also sa3"s he saw no males, which is a curious 

 fact. His statement that the caudal stylets will adhere to a sharp 

 point brought into contact with their tips, I can confirm, and I 

 have also seen a thread drawn from them in *S'. notacantlia. He is 

 confident that what I took for tracheal arches are simph" chitinous 

 rods or ligaments which serve to join the sterna and the scutes. 

 He is mistaken, however, when he affirms that the posterior ones 

 form a continuous arch, since in all the specimens examined by 

 me the arch was broken at the dorsal vessel, the widened ends of 

 the opposite halves of the arches seeming to lie against its sides. 

 The walls of these arched tubes showed double contours under the 

 microscope, which proves them to be hollow. 



He also finds four Malpighian tubules in S. immaculata, whereas 



I find but two in S. notacantlia. He finds as few as seventeen 



joints in the antennas to as manj' as fortj^-two. I find from four- 



. teen to twentj'-eight in two species. Newport,^ speaking of the 



species studied by Menge, finds the joints of the antenme to vary 



1 ^[onograijli of the Class Myriapoda, Order Chilopoda. Trans. Liuu. 

 Soc. XIX, pp. 349-439, 1 PI. 1845. 



