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SUMMARY OF CURRENT RESEARCHES RELATING TO 
observed at Plymouth, are of two kinds, — a slow gliding movement and 
a sudden dart of lightning swiftness. During the slow movements, the 
antennules or first antennae (usually held to be the most important 
locomotor organs) are held rigidly extended at right angles to the long 
axis of the body, their appearance suggesting the idea that one of their 
functions may be to act as hydrostatic sense-organs. The movement is 
effected principally by means of the second antennae (as in the Nauplius), 
the gnathites also assisting, especially the second maxillae. It seems 
probable that feeding is carried on during these slow movements. The 
quick movements are effected entirely by the simultaneous action of the 
four pairs of powerful thoracic paddles. He notes, however, that in 
the fresh-water Cyclojps the first antennae do assist in the slow move- 
ments. 
Statocyst Function.* — Th. Beer finds that Penseus membranaceus 
is well-suited for illustrating the equilibrating function of statocysts. 
When these organs are extirpated, the animal fails to keep its balance 
in swimming; it falls to one side, or in an unnatural position on the 
ground. 
Annulata. 
Polychaetes of Brest and of Paimpol.f — Baron de Saint- Joseph 
describes a small collection of Annelids from these localities, and con- 
trasts generally their fauna with that of Dinard. The paper contains 
notes on habits and distribution, and also a description of a remarkable 
new form, Pilargis verrucosa g. et sp. n., which seems to be related to 
Webster’s Phronia tardigrada Webst., and for which the author erects 
a new family, the Pilargidid^. 
Development of Oligochaetes.j; — Dr. R. W. Hoffmann has investi- 
gated some points in the development of Allolobophora putris Hoffm., 
whose embryos, on account of the small amount of albumen present, are 
well-suited for embryological work. As to the development of the 
alimentary canal, he finds that the gastrula arises by invagination, and 
that the blastopore becomes directly converted into the mouth. The 
stomodaeum originates from very large cells near the excretory cells, 
and at the same time the archenteron closes up. The stomodaeum grows 
out into a slender hyaline tube, which later acquires an S-shaped curve. 
Of the parts of the stomodaeum the pharynx is the first to be differ- 
entiated, and it certainly arises from ectoderm. Of the parts of the 
mid-gut the oesophagus is the first to be differentiated, crop and gizzard 
arise from a swelling behind it, and the remainder of the mid-gut 
becomes the intestine with its typhlosole. Contrary to Wilson’s obser- 
vations, the author finds it easy to distinguish proctodseum from mid-gut ; 
for until late in development the proctodaeal invagination is differentiated 
by its physical and staining reactions. He finds that at the time when 
the proctodaeum first opens into the mid-gut, the former extends through 
four segments of the body, but, as segment formation is still going on, 
it is probable that ultimately the ectodermal hind-gut occupies seven 
or eight segments of the body. 
* Pfluger’s Arch. f. Physiol., lxxiv. (1899) pp. 361-82. See Zool. Central bl., vi. 
(1899) p. 631. f Ann. Sci. Nat., x. (1899) pp. 161-94 (1 pi.). 
} Zeitschr. f. wiss. Zool.. Ixvi. (1899) pp. 335-57 (2 pis. and 5 figs.). 
