39 Crust. 
CRUSTACEA. 
Branchijjus arcticus (Verrill), var. ? from Discovery Bay ; Miers, in 
Nares’s Narrative, &c., ii. p. 246, pi. iii. fig. 1. 
Apodidj:. 
Lepidurus couesi (Packard, 1875) and hilobatiis, spp. nn., Verrill, Bull. 
U. S. Geol. Surv. iii. [1877] pp. 177 & 178, Montana and Colorado. 
Lepidurus hirki and compressus, spp. nn., Thomson, Tr. N. Z. Inst. xi. 
. 260, pi. xi. figs, E 4 & 6, New Zealand. 
P 
LiMNADllDJ]. 
Limnadia hermanni (Brongn.) [lenticularis^ L.]. Note on its occurrence 
in Mecklenburg ; only specimens of the size of 8 mm. and with 22 pairs 
of feet have been found, but including females with well-developed egg- 
clusters, to the end of August ; segmentation of the body, nervous 
system, and ovary described. No male has been found. F. Spangenberg, 
wiss. Zool. XXX. suppl. pp. 474-492. 
Eulimnadia ampleximana^ sp. n., Packard, Bull. U. S. Geol. Surv. iii. 
[1877] p. 174, Kansas. 
Lymnetis [Amw-] hrevifrons^ sp. n., id. 1. c. p. 172, woodcut, Kansas, 
compared with some other species. 
CLADOCERA. 
A. Weismann discusses the highly-coloured spots found in some 
Cladocera^ most striking in Latena, also in Sida, Holopedium^ Bytho- 
trepheSj Polyphemus, and Eurycercus, and exceptionally in some speci- 
mens of Daphnella hrachyura and Daphnia pulex. In Eurycercus {lamel- 
latus^ these coloured spots are limited to the female, in the others they 
occur in both sexes and in parthenogenetic females, but are generally 
most beautiful in the females during the sexual period. The author 
thinks that they are purely ornamental, and appeared originally on the 
females as an attraction for the males (in Sida, which rests in a reversed 
position, they are only on the ventral side), and afterwards passed by 
heredity to the males and parthenogenetic females. As in Sida crystallina, 
the spots are different in specimens from different captures ; the author 
concludes that these ornamental colours were acquired after the ice-period 
of Middle Europe. The numerical relations of the sexes are also dis- 
cussed, with the conclusion that generally at the beginning of the sexual 
period the males are fewer than the females, but afterwards, if not in 
equal numbers, at least in sufficient for fecundating all the females. As 
to the sexual differences, the antennae and their olfactory filaments are 
generally more developed in the males, but are in Bythotrephes equally 
poor and in Latona equally richly developed. Z. wiss. Zool. xxx. suppl. 
pp. 123-165, pi. vii. ; abstract in Nature, xviii. p. 226. 
W. Kurz discusses the peculiarities of those Cladocera which live on 
muddy ground ; they are generally clumsy, vaulted and broad, thick- 
skinned, with relatively short natatory organs, mobile feelers and reduced 
