178 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
like ” drops, containing a substance which turns yellow with the osmic 
acid and cochineal treatment. 
As more or less new, the author emphasizes what he has to say in 
regard to the lacunar state of the transitional epidermis, the develop- 
ment of the setae, the genetic homology between cirri and elytra, the 
occurrence of unicellular glands in the rudiments cf the cirri, the struc- 
ture of the ventral papillae, whose central cells are regarded as luminous, 
the origin of the brain from three distinct parts, the extension of the area 
of growth in the terminal region of the body, the development of the 
gullet from a paired diverticulum of the stomodasum (cf. Lojpadorhynchus ), 
the formation of longitudinal canals within the degenerating “ inner cel- 
lular layer ” of the gullet, the arrangement of different cell-types as 
terms in a developmental series, the structure of the longitudinal muscle 
cells, the appearance of the ventral longitudinal vessel in the Nectochaeta 
stage, the close connection between the ectoderm and a mesodermic pro- 
liferation in the formation of “ secondary ” segments, the provisional 
nephridia in the seven “ primary ” segments, the occurrence of rudimen- 
tary gonads in the most anterior segments of the Nectochseta, and the 
difference between the karyokinesis in the gonad-rudiments and that in 
the vegetative tissues. 
History of the Archoplasm Mass in Spermatogenesis of Lum- 
bricus.* — Mr. G. A. Calkins applies the term of Archoplasm mass to 
the body which acts like an attraction centre in the early germ-cells, and 
which finally becomes the middle piece of the mature spermatozoon. 
This mass is quite conspicuous, and not difficult to demonstrate if the 
proper stains are employed. Any nuclear stain is sufficient to reveal its 
presence, but Kleinenberg’s hsematoxylin and the iron-haematoxylin of 
Heidenhain give the best results. The spermatid is attached at one end 
to the spermatophore, and the division plane by which it is formed is 
radial. The elongation of the spermatid takes place radially to the 
centre of the sphere, and the centrosome is compelled to move through 
a right angle towards either the future tail end of the spermatozoon or 
the future head end. As a matter of fact it invariably moves towards the 
tail end. Preparations of different stages show that the archoplasm 
mass and the middle piece of the spermatozoon are one and the same 
substance. This identity furnishes a clue to the solution of the ap- 
parent contradiction between such cases as are afforded by Echinoderms 
on the one hand and the Axolotl on the other. 
Excretory Function of Midgut in Worms. j — Herr W. Schimke- 
witsch finds that when Dinophilus is fed with pigment, e. Algae 
coloured by indigo-carmine, the pigment is taken up by vacuole-like 
granules in the epithelial cells of the midgut. Similar results were 
got with Polynoidse, and with Pliyllodoce maculaia, Priapulus, &c. It 
seems as if the midgut cells had the power of taking up pigments from 
the gut. 
Earthworms of Florida and Georgia.^ — Hr. W. Michaelsen finds 
that the earthworms of this region are distinctly North American in 
* Trans. New York Acad. Sci., xiii. (1894) pp. 133-9 (11 figs.). 
t Biol. Centralbl., xiv. (1894) pp. 838-41. 
X Zool. Jahrb. (Spengel) Abth. f. Systematik &c., viii. (1894) pp. 177-94. 
