36 
suhhary of current researches relating to 
nient of the true intromittent organs, and probably alter the pressure 
on the ejaculatory canal. 
Spermatogenesis in Locustidae.* — M. A. Sabatier has studied the 
development of the spermatozoa in Locusta viridissima , Decticus 
albifrons , and D. griseus. He finds that a vesicle becomes formed in 
the protoplasm, and that it is placed near the caudal pole ; he calls 
it the protoplasmic vesicle. This vesicle grows and elongates and its 
walls become invested internally with chromophilous granules. When 
it is fusiform in shape and takes stains freely it forms what has been 
regarded as the head of the spermatozoon. The grains of nuclein 
in the nucleus become vesicular and form a group of vesicles which 
fuse, lose their affinity for the nuclear stains, and form an anchor- 
shaped head-covering. The degeneration of the nucleus qua nucleus is, 
therefore, one of the principal characters in the spermatogenesis of the 
Locustidae. The protoplasm of the cell elongates in the form of a tail, 
in the axis of which appears a filament which forms the tail of the 
spermatozoon. 
y . Frototracheata, 
New Species of Peripatus from Victoria. — Mr. A. Bendy writes 
to ns to say that he regards Peripatus insignis mentioned in our note f as 
a good species, and as distinct from the specimens which, after some 
trouble, he recognized as examples of P. leuckarti, Several specimens of 
P. insignis have been found at Macedon. 
5. Arachnida. 
Structure of Nerve-centres of Limulus.^ — M. H. Viallanes describes 
the minute structure of the nerve-centres of the King-Crab. The proto- 
cerebrum is composed of relatively small fibrous nodules and is partially 
invested by a cortex of large unipolar cells. The nerve for the compound 
eye is not directly connected with the corresponding cerebral lobe, but in- 
termediately and by a structure which is comparable in its essential points 
to the optic lobe of Insects and Crustaceans. With each of the proto- 
cerebral lobes there is connected an organ which, from its anatomical 
relations and histological structure, may be compared to the peduncu- 
lated body of Insects. In Limulus this pedunculated body is arbores- 
cent in form, its upper extremity dividing dichotomously into a large 
number of branches. These last, which end in truncated extremities, are 
entirely invested by a thick cortex of small cells ; they are very poor 
in protoplasm, stain deeply, give off very fine fibrils, and, in a word, 
are exactly comparable to the elements which form the cellular invest- 
ment of the similar body in Insects. The pedunculated body of Limulus 
is extraordinarily developed, and is larger than in any known Arthropod, 
for it forms at least 99/100 of the total mass of the brain. 
The hinder brain is composed of a pair of nervous masses which 
give origin to the nerves of the chelicerae, and are connected with 
one another by a transverse peri-cesopbageal commissure. This latter 
is invested by a very resistant fibrous sheath. The lateral parts of the 
* Comptes Rendus, cxi. (1890) pp. 797-9. t See this Journal, 1890, p. 453. 
X Comptes Rendus, cxi. (1890) pp. 831-3. 
