232 P. G. HEATHOOTB. 



Literature. 



But little work has been done on the early development of 

 Chilognatha. According to Newport, De Geer was the first to 

 watch the development of Julidse (6). He observed that 

 Julus and Polyxenus were hatched with three pairs of limbs 

 and a fewer number of body segments than is possessed by the 

 adult animal. 



Savi was the next observer. In 1817, in a paper quoted by 

 Newport (11) and which I have not been able to obtain, he 

 said that Julus was hatched without limbs. The next observer 

 was Waga. In 1840, he, in a paper quoted by Newport (11), 

 states that the young Julidse are completely apodal at the time 

 of hatching. Gervais (8), the next observer, in 1844, gives a 

 great deal of fresh information about the later development of 

 Chilognatha, but has little to say with regard to the earlier 

 stages before hatching. He tells us, however, that Glomeris 

 marginata has three pairs of limbs before hatching; that 

 Polydesraus complanatus has also three pairs when 

 hatched. 



Fabre (7) in 1855, investigated the development of Poly- 

 desmus, and describes it as having three pairs of limbs and 

 eight body segments, including the head segment, at the time 

 of hatching. He also investigated Julus aterrimus, and 

 describes it as hatching on the fifteenth day, being then 

 apodous and without any organ or appendage, and the shape of 

 the body being reniforra ; five days afterwards, he tells us, that 

 he observed the first traces of body segmentation, and that 

 seven days after hatching the animal consisted of eight body 

 segments and possessed three pairs of limbs. 



Metschnikoff found that the young of Julus Morreletti 

 were hatched with three pairs of limbs (9), while Newport found 

 that in Julus terrestris the just hatched young only pos- 

 sessed the rudiments of three pairs of limbs, and faint traces 

 of the antennse. My own investigations, which were carried 



