ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
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species of Scalpellum. In most Lepadidra, such as Lepas, Conchodcrma 
virgatum , or Scalpellum vulgare , six stages arc recognized, a nauplius, a 
modified nauplius (with slight modifications in shield and appendages), a 
metanauplius (with a fourth pair of limbs, rudiments of cirri and attaching 
disc, &c.), a Cypris stage (with a bivalve shell), a G Y ypm-pupa (after 
attachment), and finally a Cirriped. In certain deep-sea species of 
Scalpellum the developmental stages found within the capitulum are 
divergent. In Sc. septentrionale and Sc. erosum the first stage is dis- 
tinctly a metanauplius, which is, however, unable to swim ; in Sc. obesum , 
Sc. cornutum, and Sc. prunulum the stage observed within the capitulum 
was a Cypris , also with limited powers of locomotion. Thus there is 
(1) an abbreviation of the normal post-embryonic development, for the 
nauplius stage is passed before hatching ; (2) a peculiar metanauplius 
and Cypris stage, modified apparently in relation to prolonged retention 
within the maternal capitulum. As the author points out, we have here 
a good illustration of the manner in which nearly related forms may show 
divergent developmental adaptations to different conditions of life. 
Parthenogenesis of Artemia.* — Dr. A. Brauer describes the process 
of maturation in the parthenogenetic ova of Artemia salina. It takes 
place in two ways ; in the one case the segmentation spindle contains 
84 chromosomes, in the other 168 ; the half of the first directive spindle 
may directly become the segmentation-nucleus, or a second division may 
occur without extrusion, and the two halves may form the segmentation 
spindle. The first process is by far the more frequent. The remarkable 
difference in the number of chromosomes may be seen in later cleavage 
stages ; it persists ; but the author believes only some of the ova with 
168 chromosomes are capable of development. There is a single centro- 
some, which is very distinct in association with the segmentation nucleus, 
but very indistinct in association with the directive spindles, and Brauer 
is not inclined to credit it with any import except in connection with 
division. He calls it a Theilungsorgan. 
A study of abnormal segmentation, which is very common, leads 
Brauer to the conclusion that the abnormality is not due to environ- 
mental conditions, but is directly associated with the parthenogenetic 
development, that it is due to deficiency of chromatin caused by the 
extrusion of a second polar body. This extrusion has been observed, 
and Brauer points out that in the cases of Liparis where two polar bodies 
have been observed to be extruded from parthenogenetic ova, it has not 
been sufficiently proved that the ova are in such cases capable of develop- 
ment. In the case of the bee, Blochmann’s proof of the extrusion of a 
second polar body is not very satisfactory. 
Harpacticidse.'t' — Dr. O. Schmeil continues his description of the 
freshwater Copepods of Germany, dealing now with the Harpacticidse. 
Hitherto the subfamily of Canthocamptinse has included all the German 
forms, but the author has discovered Ectinosoma Edwardsi which repre- 
sents the subfamily Longipedinse. The absence of a prehensile hook 
on the second maxillipedes is distinctive of this subfamily. Schmeil 
* Arch. f. Mikr. Anat., xliii. (1894) pp. 162-222 (4 pis.). 
t Bibliotheca Zoologica (Leuckart and Chun), Heft 15 (1893) pp. 1-101 (8 pis., 
2 figs.). 
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