181 SIR JOHN LUBBOCK ON PAUROPUS. 



• 



probably the generative organs. They do not appear to be present in all specimens, and 

 belong to the male sex, as in one case I saw them distinctly in a specimen which was 

 fnll of spermatozoa. In one case I traced two tnbes opening into them. On the under- 

 side of the anterior segment of the body, in front of the first pair of legs, are two 

 pairs of leaf-like hairs, like those on the coxge and femora of the legs. These evidently 

 indicate the presence of an anterior aborted pair of legs. 



The dorsal hairs are also remarkable. The long ones, of which there are a pair to each 

 segment, are ringed and delicately plumose. The lateral seta?, however, are short and 

 extremely delicate. The short scattered bristles are arranged in rows across the back ; 

 except the first two and last two, each segment has two rows of them ; there are about 

 six in each row ; they are stiff and club-shaped (as shown in Plate X. fig. 6). 



At the posterior end of the body (Plate X. fig. 17) are several other stiff spines, and 

 two minute forked processes. 



Several specimens contained large numbers of spermatozoa, which are filiform 

 (Plate X. fig. 16) with a small head at one end. I never saw them in motion. 



Though the animal is tolerably transparent, and the digestive organs are plainly 

 visible, I never could see any trace of tracheae. Being so small and delicate a creature, 

 it is probable that the respiration is carried on through the skin : but if this is the case, 

 Tcmropus presents us with another very important peculiarity, — all other Myriapods, so 

 far as we know, possessing tracheae. 



The smallest specimens which I have met with were about -^ of an inch in length, 

 and possessed three pairs of legs only (Plate X. fig. 18). The first pair was attached to 

 the third segment {i.e. the one immediately succeeding the head), the other two to the 

 following one. Beyond the legs were two other segments, making six in all, as seen 

 from above, and counting the head as two. The fourth and fifth segments each bear a 

 pair of long bristles, as in the fuU-grown form : the first pair point outwards and forwards, 

 the latter outwards and backwards. The general arrangement of the hairs and of the 

 short caudal processes is the same as in the large specimens; and the antenme are 

 formed on the same plan. 



I found the first of these six-legged ones on the 11th of September ; but I am not 

 prepared to say that they might not have been met with earlier if they had been looked 

 for. They continued tolerably numerous throughout the autumn, and occurred in the 

 same localities as their parents. 



The development of Pauropus, at least in captivity and during winter, is far from rapid. 

 A specimen with three pairs of legs, captured on the 24th of October, has not yet un- 

 dergone any change *. It remains to be seen whether under more favourable 



circum 



the growth may not be quicker 



This specimen died on the 6th of December. Another, captnred on the 23rd of November, lived for a month 

 without change A third, caught on the 3rd of November, survived until the 20th of February. A specimen 

 mft six purs of legs, caught on the 20th of October, also lived till the 8th of February, without change. Another, 

 with eight pairs of legs, lived from the 30th of September to the 5th of November, when it met with an accident, 

 observed also in Chloeon that my lame remained with scarcely any change during the winter months (see 



Linn. Trans, vol. xxv.V ° ° 



Linn. Trans, vol. xxv.). 



