776 
ME. H. N. MOSELEY ON THE STEUCTUEE AND 
in development, and the absence of any trace of primitive three-legged condition, taken 
in conjunction with the divarication of the nerve-cords, are conclusive. The parts of the 
mouth are not to be regarded as degraded to any great degree ; and homologies for 
some of them, at least, may perhaps be found amongst the higher Annelids. The struc- 
ture of the skin is not at all unlike that in some worms, especially in its chitinous 
epidermic layer, which strips off in large pieces occasionally as a thin transparent 
pellicle. The many points of resemblance of Peripatus to Annelids need not be dwelt 
upon ; they led to its former placing in classification ; but it is difficult to understand 
how the very unannelid-like structure of the foot-claws did not lead others, like De 
Quatrefages, to draw a line between the two. In being unisexual, Peripatus is like 
the higher Annelids, as well as the whole of the higher Tracheata. To Insects Peri- 
patus shows affinities in the form of the spermatozoa, and the elaboration, structure, 
and bilateral symmetry of the generative organs, though there is a very slight tendency 
towards the unilaterality of Myriopods in the male organs. 
To Insects, again, it is allied by the five-jointing of the feet and oral papillse and the 
form and number of its claws. It should be remembered that spiders’ feet are two- 
clawed, and those of some Tardigrades, and that some of these latter forms have 
two-clawed feet in the early condition, even when they possess more claws in the adult 
state. In Newport’s well-known figure of the young lulus with three pairs of limbs, 
the tips of these latter are drawn with two hair-like claws ; these are not mentioned 
in the text. 
To the ordinary lepidopterous larva the resemblances of Peripatus are striking — the 
gait, the glands (so like in their function and position to silk-glands), the form of the 
intestine, the less perfect concentration of the nervous organs in larval insects. To 
Myriopods Peripatus is allied by the great variety in number of segments in the various 
species and in its habits, and especially in these to lulus. The parts of the mouth 
perhaps show a form out of which were derived by modification those of Scolopendra ; 
but the resemblance may be superficial. Our knowledge is not yet sufficient to deter- 
mine such points. The usual difficulties occur in the matter. Segments may have 
dropped out or fused, and their original condition may not be represented at all in the 
process of development. In structure Peripatus is more like Scolopendra than lulus , 
viz. in the many joints to the antennse (Chilognaths having never more than fourteen), in 
the form of the spermatozoa, and in being viviparous, as are some Scolopendras ; in the 
position of the orifices of the generative glands, and in the less perfect concentration 
mesially in Scolopendra of the nerve-cords. Peripatus thus shows affinities in some 
points to all the main branches of the family tree of Tracheata ; but a gulf is fixed 
between it and them by the divarication of the nerve-cords, and borne out somewhat 
by such facts as the non-striation of the muscles, great power of extension of the body, 
arrangement of the digestive tract in the early stage, persistence of metamorphosis, and 
in the parts of their mouth, the full history of the manner of origin of these being 
reserved. 
