ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
473 
case, the ovum-nucleus contains 84 bipartite chromosomata ; in the 
second case it contains 84 single chromosomata. In the first case, the 
equatorial plate of the first segmentation spindle has 84 chromosomata, 
in the second case 168 ; but the second case is rarer. The larger 
number is the normal. It is interesting to find that the occurrence of 
two divisions is compensated for by the subsequent union of the second 
directive-nucleus with the too much reduced ovum-nucleus. Brauer’s 
results are in harmony with those of Boveri and 0. Hertwig in regard to 
parthenogenesis. 
Podopsis.* * * § — Mr. F. H. Herrick brings forward evidence to show 
that the remarkable Schizopod genus described, in 1829, by J. Vaughan 
Thompson as “ Podopsis,” or the Hammer-headed Shrimp, is a larva of 
Stenopus. No other allusion to the genus has been found by the author. 
Mr. Herrick points out that the form figured by Thompson is strikingly 
like the Stenopus- larva figured on plate xii. of his account of the Life- 
history of Stenopus ,j* In the enormous eye-stalks, the antennae, the 
huge size of the third pair of maxillipeds, the configuration of the body 
and of the tail-fin, there is a very close agreement between “Podopsis” 
and the Mastigopus-larval-stages of Stenopus hispidus. 
Vermes, 
a. Annelida. 
Peculiarities in Segmentation of Polychsetes.J — Miss F. Buchanan, 
referring to Cori’s recent paper § on abnormalities in the segmentation 
of Annelids, points out that there is at least one family of Polychaeta in 
which cases of intercalation and spiral segmentation are so common 
that they may be regarded rather as normal individual variations than 
as abnormalities. This family is that of the Amphinomidae. 
In fourteen specimens of the subgenus Eurythoe from Torres Straits 
six have each a half-segment completely or incompletely intercalated ; 
in Linopherus one of two specimens has two and a half of its segments 
arranged as a right-handed spiral. In seventeen specimens of Eurythoe 
from the Gulf of Manaar two have intercalated half-segments, and six 
have spirals of varying lengths. Of fifty specimens of Amphinome in 
the British Museum, twenty-seven present variations in symmetry of one 
kind or another ; of thirty-three examples in the same collection of the 
subgenera Eurythoe and Hermodice, a dozen appear to present irregu- 
larities in segmentation ; of these the most remarkable is the specimen 
in which one spiral of two coils begins in the middle of and intertwines 
with another of seven. 
Other examples are cited, including the very distant Pentasiomum , 
and reference is made to Cori’s observation of intercalations of half- 
segments in Cestodes. 
It is as yet too early to assign a cause to these variations, but some 
objections to regeneration are offered, and it is pointed out that the 
spiral arrangement may still require explanation. 
* John Hopkins Univ. Circ., xii. (1893) p. 104. 
f Mem. Nat. Acad. Sci., v. (1892). 
t Quart. Journ. Micr. Sci., xxxiv. (1893) pp. 529-44 (1 pi.). 
§ See ante, p. 38. 
