494 
VERMES. 
are two copulatory organs ou the dorsal side of each reproductive segineut 
in the males ; in the females, the oviducts occupy the same position, while 
the vulvoo (leading into the copulatory pouches) are placed on the ventral 
aspect. In Lelpoceras uviferum, Momus has detected on the sides of the 
body, from the 18th segment onwards, tubercles, becoming racemose on 
the hinder segments : these are egg-bundles or external ovaries and the 
same segments have eggs on the inner surface of the body-wall. Zweite 
deutsche Nordpolarfahrt, ii. pp. 254 & 255. 
In Greeff’s anatomical account (6) of Echiurus pallasi and Thalas- - 
sema haroni, one of the chief points is, that the principal trunk of the 
nervous system, a single cylindrical string reposing immediately on the 
ventral surface of the inner circular muscular layer, is entirely without 
vestiges of ganglia, though it has been figm*ed as a regular chain of 
ganglia. The oesophageal ring also is not existing, as described ; but the 
abdominal string divides where it enters the spoon-shaped proboscis, the 
two branches uniting again at the broad end of this organ. 
Perrier’s “ ^Itudes” (17) is the first — on the anatomy of Urochceta — 
of an intended series of papers devoted to the investigation of the exotic 
types of earth-worms ; these may be studied conveniently in Europe, 
when sent in company with living plants for hot-houses, etc. Perrier 
draws attention particularly to the chapters treating of the systematical 
value of the characters furnished by the locomotive bristles, of the nature 
and physiological action of “ Morron’s glands,” and of the circulatory 
apparatus. [A summary of the most important discoveries must be 
deferred until the intended series is concluded.] An abstract of Perrier’s 
previous paper in N. Arch. Mus. viii. [Zool. Rec. ix. p. 467] is given in 
J. Zool. ii. pp. 213-216. 
Tauber (18) haS studied the anatomy, histology, and asexual repro- 
duction, &c., of the Naidea, especially of Stylaria proboscidea, Nais 
elinguiSj Choitogaater limncvi and C. diaphana. His experiments on the 
artificial division and regeneration of these Oligochcata have confirmed 
those made by 0. F. Muller a century ago. Taking as his starting-point 
a number of primary stem-animals, especially of Nais elinguis, developed 
direct from the egg, he has, for a year and a quarter, continued watch 
ing and carefully isolating each stem-animal (primary or secondary, &c.) 
from its chained offspring, ascertained several important and hitherto 
dubious facts concerning the so-called “transversal division” or “spon- 
taneous fission ” of these Annulata. A true “ fission ” or “ division ” how- 
ever never takes place ; the phenomenon to which this name has been given 
is, in fact, a gemmation, not only when, in the ordinary gemmation, 
segment after segment of the stem-animal is sacrificed for the forma- 
tion of new “ zooids,” but also when (this process having attained its 
natural limit, and the consumed segments being reproduced) a new “divi- 
sion ” apparently takes place through the formation of a new head in 
the middle of the elongated body ; or when the same process is going on 
at the first division of the primary egg-hatched stem-Naid : the only 
difference is, that in the last instance the formation of the head, &c., is 
retarded relatively to the other segments. In the beginning of the 
second life-year, the primary stem-individuals acquire sexual maturity, 
