THE MYRIAPODA. 341 



that face of the embryo become closely applied together. 

 Metschnikoff further points out that only two pairs of ap- 

 pendages are converted into gnathites, and that a chitinous 

 cuticula, apparently identical with what Newport describes 

 as the " amnion " in lulus, is early thrown off from the em- 

 bryo. In some species it develops a median tooth-like pro- 

 cess, which serves to burst the vitelline membrane. New- 

 port describes a short cord, or funiculus, which connects the 

 anal extremity of the embryo with the so-called " amnion." 

 It is not improbable that this is simply the continuation of 

 the first larval skin into the rectum. 



The embryo lulus at first bursts the vitelline membrane, 

 and is inclosed only in the embryonic integument. At this 

 period its body is divided into eight segments, of which the 

 first represents the head. Traces of the antennae are visible 

 on the sides of the head, and the four following segments 

 exhibit papillae ; those of the second, third, and fifth segments 

 develop into the three pairs of functional limbs, with which 

 the young myriapod is at first provided. 



Between the terminal segment and the seventh the body 

 grows and becomes divided into six rudimentary new seg- 

 ments. The terminal segment also becomes divided into 

 two. Thus, when the young escapes from the embryonic 

 integument, it consists of nine complete segments, including 

 the head, with six rudimentary segments interposed between 

 the penultimate and the antepenultimate — making fifteen in 

 all ; which is the full number of segments (head + three tho- 

 racic -f eleven abdominal somites) possessed by an insect 

 larva. 



There is this difference, however, between the insect and 

 the larval myriapod : that since, in the latter, there are only 

 two pairs of gnathites, which must answer to the mandibles 

 and first maxillae of insects, the ambulatory appendages of 

 the second segment must represent the second maxillae of 

 insects ; and hence, though there is apparently the same 

 number of somites in the two cases, there must in reality be 

 one fewer in the myriapod. The myriapod larva, therefore, 

 notwithstanding its hexapod character, is essentially differ- 

 ent from an insect larva. 



The sixth and the seventh segments develop two pairs of 

 legs, as do all the newly-formed segments ; and it is worthy 

 of notice that the male copulatory apparatus, inasmuch as it 

 is situated in the seventh (sixth postcephalic) segment in the 

 adult, is developed from one of the primary segments of the 



