JUNE 14, 1912] 
stored in all except one case; in this animal there 
was a change from single to multiple parts which 
included both polian vesicles and retractor muscles. 
A full account with discussion of these results 
will be given in the Journal of Experimental 
Zoology. 
The Distribution of North American Earthworms: 
F. SmiTH, University of Illinois. 
In North America north of Mexico, scarcely 
fifty species of earthworms are known, which is 
less than five per cent. of the known species of 
the world. This small number is due in part to 
lack of study, but also to an actual lack of the 
variety usually found in territories of similar 
extent. 
The genus Diplocardia is very characteristic of 
the region and includes species from Illinois, Ne- 
braska, North Carolina, Georgia, Florida and Mex- 
ico. Other parts of the United States east of the 
Rocky Mountains doubtless have species. Diplo- 
cardia is a very primitive type of the family 
Megascolecide and probably originated in North 
America as early as the Jurassic. i 
West of the Rocky Mountains are found a few 
species of Plutellus and Megascolides, of which 
genera the remaining species are found in Aus- 
tralia and India. These are primitive forms of 
Megascolecide which presumably originated in 
Australia and representatives migrated from there 
during the Jurassic and Cretaceous by way of 
Siberia and Alaska into the Pacific region of 
North America. 
The family Glossoscolecide is represented by the 
primitive aquatic genus Sparganophilus, of which 
species are known from Florida, the Mississippi 
Valley, California and Mexico. This genus prob- 
ably originated on this continent as early as the 
late Jurassic. 
The family Lumbricide includes the majority 
of the North American earthworm species. The 
most of them are also known in the Eurasian 
region, where they probably originated. The few 
endemie Lumbricid species of the United States 
are found chiefly in the states of the Atlantic 
Tegion. 
A few peregrine species of the Megascolecid 
genera Microscolex and Pontodrilus are found in 
the coastal regions. 
Probably few if any species will be found 
endemic in the glaciated parts of the continent. 
Studies upon the Migratory Movements of the 
Pacific Coast Lobster: BENNETT M. ALLEN, 
University of Wisconsin. 
SCIENCE 
939 
Brass tags were affixed to 346 specimens of 
Panulirus interruptus, that were released at dif- 
ferent times, at Santa Barbara, California, also at 
various points on the coasts of Santa Cruz and 
Anacapa Islands. 
In all, 26 were caught and reported by the fisher- 
men. The greatest distance traversed was 92 
miles in 28 days. The most rapid average rate 
of migration was .43 mile per day in the case of 
a specimen that traveled six miles in fourteen 
days. Eleven traveled less than one mile in an 
average of eighteen days. Hight traveled more 
than one mile in an average of twenty-seven days. 
The total average of distances traveled was lis 
miles in an average time of twenty-two days. The 
movements were haphazard. 
Of the twenty-six caught, most of which were 
again released according to request, 5 were caught 
again—a third time in all. This investigation was 
financed by the Californian Fish and Game Com- 
mission. 
The Chiasma of the Trochlearis Nerve: H. V. 
NEAL, Knox College. 
The Habits of Fiddler-crabs: A. 
Louis University. 
(To appear in the Philippine Journal of Sci- 
ence.) 
Some Glimpses of Biological Conditions in West- 
ern Nebraska: R. H. Woucorr, Nebraska Uni- 
versity. 
S. PEARSE, St. 
(1) Notes on the Rate of Growth of Freshwater 
Mussels. (2) The Fairport Biological Station: 
R. E. Coker, Bureau of Fisheries. 
(1) Karyosomes in the Ova of Passer domesticus. 
(2) Magnetic Control of the Movements of 
Paramecia which have Ingested Iron: E. H. 
Harper, Northwestern University. 
(1) In the ovary of the sparrow in the winter 
the nuclei, particularly of the smaller ova, show an 
aggregation of the chromatin into karyosomes and 
absence of the chromatin net. These bodies have 
so definite an appearance as to suggest the possi- 
bility of definiteness in number. The count 
showed the probable number to be twenty-two, 
_harmonizing with known results from the sperma- 
togenesis which indicate the haploid number of 
chromosomes as eleven. On this basis, these bodies 
in the ova may be called the prochromosomes, 
Stages in the breakdown of the nucleoli to form 
the chromatin net were also shown. : 
(2) The question is raised whether the normal 
position of stable equilibrium with antero-posterior 
