ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
177 
Blood of Magelona.*— Dr. W. B. Benham reports that the blood of 
this worm differs entirely from that of any other Cliaetopod hitherto 
examined. Instead of a red liquid plasma, in which a few nucleated 
and colourless corpuscles float, the blood-vessels of Magelona are com- 
pletely filled with very small spherical globules of a madder-pink colour 
floating in an extremely small amount of colourless plasma. These 
globules are not cells ; their colour is due to a pigment similar to 
haemerythrin. The globules themselves, when shed, exhibit a marked 
tendency to run together like oil-drops and fuse with one another. This 
peculiar and rather viscous mass seems to be intermediate in some 
respects between the absolutely liquid coloured plasma of Chaetopods 
generally, and the red corpuscles of Mammals which float in a compara- 
tively small amount of colourless plasma ; further, the globules in 
Magelona probably originate, as those of Mammals do, within cells from 
which they are released. 
Cephalic Lobe of Euphrosyne.f — M. E. G. Racovitza recalls the 
structure of the cephalic lobe of Amphinome , and points out that if 
certain series of forms of the family are studied, two tendencies may be 
observed. In the modification of the anterior extremity the parapodia 
of the first three or four segments are carried more and more forward, 
so that their axis tends to lie in the sagittal plane of the body, or the 
mouth and the lips are carried further and further back, and the anterior 
pair of eyes with the paired antennas tend to pass on to the ventral 
surface. Itlis probable that the second tendency is only a function of 
the first. These modifications are manifested in a very high degree in 
Euphrosyne , the details of which the author gives. In the course of his 
account he points out that the glandular organs of MTntosh are only 
masses of pigment deposited in the posterior lobes of the brain. Similar 
masses are found along the pedal nerves, as -well as in other Polycliseta. 
In Spinther the tendencies described by the author are even more com- 
pletely realised. The parapodia of the first segment are fused in front 
of the cephalic lobe. The caruncle, the lips, and the paired antennEe 
disappear. 
Later Development of Polynoe Larvse.t — Dr. Y. Haecker has fol- 
lowed the development of Polynoe from the formation of metameres to 
the beginning of the metamorphosis into adult form. In other words, 
he is mainly concerned with the Nectochseta stage, which is intermediate 
between the trochosphere and the adult form. This stage is marked 
by the following histological peculiarities : — (1) in the head region, 
especially in the degenerating ciliated ring, the epidermis shows large 
lacunae containing a substance which stains pale violet with alum-cochineal : 
(2) at various parts of the body, but especially in the rudiments of the 
cirri, there are numerous intracellular glandular saccules whose secretion 
becomes dark carmine red when fixed with osmic acid and stained with 
alum-cochineal ; (3) in the seven primary segments there are strongly 
developed provisional nephridia, whose contents give a similar reaction 
to that just noted ; (4) in the anterior part of the gut there are isolated 
cells whose plasma shows a uniform and dense disposition of “ pearl- 
* Rep. Brit. Assoc., 1891, p. 696* 
t Comptes Rendus, cxix. (1891) pp. 1226-8. 
t Zool. Jahrb. (Abth. Anat. Ontog.), viii. (1891) pp. 218-88 (1 pis.). 
1895 n 
