810 The American Naturalist. [September, 
20 were observed in Lake St. Clair. In the case of the inland lakes, 
collections were made from the shore only. The most abundant pelagic 
species are Polyarthra platyptera Ehrbg., Anuraea cochlearis Gosse, 
and Asplanchna priodonta Gosse, which agree, in this respect, with 
the condition found in European lakes. 
The Internal Anatomy and Relationship of Pauropus.— 
According to Peter Schmidt, whose preliminary paper appeared in the. 
Zoologischer Anzeiger, the internal anatomy of Pauropus allies it most 
closely with Polyxenus among the Diplopoda. The absence of trachea, 
of malpighian tubes and of a circulatory system, together with the 
presence of a rather complicated genital apparatus in the male, seem to 
show that it is very degenerate. That it belongs along with the Dip- 
lopoda—a fact that has been questioned—the presence of the ovary 
below the intestine, of the genital openings in the third body segment 
behind the second pair of legs, and of only two pairs of oval append- 
ages, abundantly testify. The biramose antenns may possibly be ex- 
plained by a comparison with the sense papilla at the end of the 
terminal joint of the Diplopod antenna, the more readily, too, since, 
according to Schmidt, the distal portions of the rami, the geisseln of 
Latzel appear to be finely ringed and not segmented. 
Several peculiarities are interesting. The mid-gut is without a mus- 
cularis and its epithelial cells are filled with rhomboid crystals with 
double refractive powers. The supra- and sub-cesophageal and the 
first body ganglia are fused into one mass which is pierced by a very 
short fore-gut. The small processes on the first segment bre rudi- 
mentary legs and possibly function in respiration like 
the abdominal sacs of Thysanura, Symphyla and cer- 
tain Diplopods. The sense organ of the antenne, 
the globulus of Latzel, consists of an outer and inner 
capsule with the intervening space filled with a fluid. 
The whole is surrounded by ten or twelve bristles 
while the nerve passes into the inner capsule and ex- 
pands into a nail-like head. (Fig: 1.) Fig. 1. 
The female genital apparatus consists of an unpaired ovary lying, 
beneath the intestine, an unpaired receptaculum seminis and an oviduct 
opening to the exterior by an unpaired opening to the one side of the 
median line in the third segment. In the male there is an unpaired 
testis above the intestine, a complicated pair of ducts, a pair of seminal 
‘Zur Kenntniss des inneren Baues des Pauropus huxleyi Lubb. Zool. Anz., 
XVI, 189 
