522 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
was motionless, but it was sensitive. When Mr. Betlie first saw the 
crab he imagined that this surplus leg might be innervated by a nerve 
coming from a surplus half ganglion of the right side, and this indee.1 
proved to be the case. Dissection showed a big nerve entering the leg, 
and starting from the right side of the ventral cord. A theoretical 
explanation of this abnormality is promised in a further paper. 
Classification and Distribution of Lithodinea.* — M. E. L. Bouvier 
recognises two tribes — Hapalogastrica and Ostracogastrica. Diagnoses 
are given of the genera and species. 
The Lithodinea inhabit cold or temperate waters ; they are therefore 
found in deep water in the Tropics, while they are littoral or sub-littoral 
in temperate and cold regions, The primitive forms, Hapalogastrica, 
are all littoral or sub-littoral ; and the abyssal forms are migrants from 
the shore, and less primitive. The original home seems to have been 
the North Pacific, for there the majority and all the primitive forms arc 
found. Thence some forms, following an abyssal path, have reached 
South America, where some have again become sub-littoral. Others 
invaded and still invade the Atlantic ; following two opposite routes, 
one western from south to north along the American coast, the other 
eastern from north to south along European coasts to Africa. 
Pelagic Schizopods.j* — Prof. C. Chun begins this chapter of his 
‘ Atlantis ’ with some general notes on the share which Schizopods have 
in the Plankton. Quantitatively, the Euphauskhe predominate greatly 
over the Mysideae. He passes to a description of Stylocheiron mastigo- 
phorum Chun, paying particular attention to the secondary sexual 
characters. Then follows an account of the internal structure of Stylo- 
cheiron. Four forms receive particular description — S. chelifer Chun, 
Nematoscelis mantis $ Chun, Arachnomysis Leuckartii Chun, and Bruto- 
mysis Vogti g. et sp. n. 
Chun suggests the following scheme, showing the relationships of 
Euphausidae : — 
Ancestral form 
Benthcujphausia 
I Tltysanopoda 
Nyctiphanes 
Thysanoessa 
Euphausia 
Stylocheiron Nematoscelis 
The memoir concludes with systematic notes on the following 
Mysideae : — Siriella Dana, Euchsetoma G. 0. Sars, Bratomysis Chun, 
Csesaromysis Ortm., and Arachnomysis Chun. 
Fresh-water Copepods of Germany4 — Dr. 0. Schmeil continues his 
account of these, dealing in this, the third, part of his memoir with the 
* Ann. Sci. Nat., i. 1896, pp. 1-46. 
f Bibliotheca Zoologica (Leuckart and Chun), Heft 19 (1896) pp. 139-89(7 pis.). 
% op. cit., Heft 21, pp. 1-72 (6 pis.). 
