ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
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the author appears to doubt its identity with Ixodes bovis, and the paper 
is disfigured by so many misprints as to render the meaning frequently 
obscure, but it contains numerous interesting observations on the 
methods of distribution and the life-history of the pest. The eggs are 
laid on coarse grass, and the young ticks may be blown considerable 
distances, attached to leaves or other vegetable matter or to feathers. 
Goats, kangaroos, and other mammals, many birds, and even man, also 
assist in distribution. The larvae have six legs, and attach themselves 
to each other or to blades of grass with four of these, while the anterior 
two wave freely in the air, and seize hold of any moving object with 
which they may come in contact. 
e. Crustacea. 
Complementary Male of Scalpellum.* — A. Gruvel describes the 
structure of Sc. vulgare, which in many respects follows that of the her- 
maphrodite form, though greatly simplified, e.g. in the absence of diges- 
tive canal and of specialised vascular and respiratory arrangements. On 
the other hand, it is of course marked by the enormous development of 
the male reproductive organs. The author tries to find some answer to 
the question, how the fertilised ova of the hermaphrodite give rise to 
two forms so different. It is obviously not an ordinary case of sexual 
dimorphism. His suggestion is the following. It is well known that 
in Cirripedia the spermatozoa ripen before the eggs, and it is found that 
the spermatozoa of the complementary male are usually ripe some time 
after those of the hermaphrodite. The first ova of the hermaphrodite 
are probably fertilised in the ovigerous sac by the spermatozoa of the 
hermaphrodite which have previously accumulated in the interpallial 
space. As the eggs develop, the holes piercing the ovigerous sac become 
more oblique and finally close. The sac is detached from the genital 
atrium and is fixed to the ovigerous frenum. Thereafter some belated 
eggs are still liberated, and these are probably fertilised by the sperma- 
tozoa of the complementary males. On this supposition the author 
thinks it is easier to understand the dimorphism, for he finds it difficult 
to believe that similar eggs fertilised by similar spermatozoa could give 
rise to larvae which are destined to turn out so differently. 
Development of Parasitic Copepoda.f — Herr W. Scliimkewitsch 
publishes a short note supplementing his previous observations on this 
subject. He finds that the asymmetry previously described in the deve- 
lopment of the genital cells of Notoptcrophorus is apparent and not real ; 
the genital cells originate from four cells and not from two as previously 
described, but the four do not sink in at exactly the same time. The 
ectodermal thickening seen in parasitic Copepoda probably corresponds 
to a similar structure in Neomysis vulgaris which gives rise to the ecto- 
dermic investment of the embryo. The flattened cells which overlie 
the endoderm, and which were previously regarded as constituting the 
splanchnic layer of the mesoderm, the author now considers to be homo- 
logous with the mesenchymatous cells of Meyer in Psygmobranchus. 
* Arch. Biol., xvi. (1899) pp. 27-47 (1 ph). 
f Zool. Anzeig., xxii. (1899) pp. 111-14. 
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