a ee eae eT ee a 
sh pee PE TRE E ie So cei S S AEE A VEE E E y 
1883.1] Zoölogy. 329 
of swimming legs in those specimens in which the appearance of 
the legs is most clear.” In some of the figures the legs appear to 
be much in form and length as in the Lysiopetalidz. In speaking 
of the legs, Mr. Scudder seems to have in mind only the even- 
jointed legs of the Julidæ; but those of the Lysiopetalide resem- 
ble the legs of the Archipolypoda in having the joints very un- 
even ; the third joint being about one-third as long as the entire 
g. Moreover, the legs of certain existing Myriopods are, if we 
mistake not, more or less flattened. Besides the second pair of 
legs in Sphzropceus, which are flattened, adapting them for 
clasping ; those of certain Ceylonese Julidz, figured by Humbert 
(pl. 1v., fig. 19% and 21g), have broad expansions on some of the 
joints, though the legs end in claws. The legs of Euphorberia 
and all the other Archipolypoda end, apparently, in sharp points, 
and this indicates that they must have had sharp claws, We 
do not see that the form of the feet indicates aquatic habits; had 
they been adapted for swimming we should have expected that 
=e form would have been more or less spatulate and without 
claws, 
_A singular feature of the Archipolypoda are “ peculiar organs, 
situated one on either side of the median line, at the very front 
edge of the ventral plate; to these it seems to be impossible to 
assign any other function than that of support for branchiz ; they 
consist of little tringular cups or craters, projecting from the under 
surface, through which I believe the branchial appendages pro- 
ed; so far as I am aware, no other organs than branchiz have 
been found in any Arthropoda situated within the legs, and re- 
Peated in segment after segment.” These structuresare certainly 
remarkable, and suggestive of branchial supports, and it is to be 
hoped that fossils will be discovered, with remains of the branchize 
themselves. Whether an aquatic, swimming branchiate Myriopod 
would have such large spiræles may be questioned. But at any 
rate the Archipolypoda are a most interesting group, whatever be 
our views as to their position and nature; they. may be regarded 
as larval forms, and in some degree as synthetic forms, with no 
modern representatives, Still, we should not exclude the type 
from the Chilognaths, though, perhaps, forming a suborder of the 
ilognaths, assuming that the Myriopods should rank as sub- 
class. Thus the order of Chilognaths might be divided into two 
suborders, the lower and more larval and extinct group being the 
Archipolypoda, and the higher the genuine Chilognaths. In 
has connection it may be observed that. the embryo Chilognaths 
ient stages new segments are added, from each of which 
wo pairs of legsarise. The possession of two pairs of legs, then, 
ain Secondary and acquired character. We have a parallel to it 
en ty of F hyllopod Crustacea, the Apodidz, in which from 
ee SIX pairs of legs in post-larval life arise from a single seg- 
—A. S. Packard, Fr, a. 
