ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
631 
Unlike Hensen, who previously described the organs, Be the finds a distinct 
opening in the cyst. He describes the statolith minutely, and proves 
the presence of calcium fluoride instead of the usual calcium carbonate. 
After describing the basal cushion, the sensory hairs, and the innervation, 
he corroborates Hensen’s discovery of free sensory hairs outside the 
cyst. The otocyst developes as an invagination of epithelium, and its 
function is experimentally shown to be equilibrating, though an auditory 
function is not excluded. 
Spermatogenesis of Telphusa.* — Dr. M. Muri describes the main 
stages in the spermatogenesis of this freshwater crab. He finds them 
closely parallel to those in Astcicus fluviatilis, which he attributes rather 
to similarity of conditions than to relationship. 
Luminosity of Metridia longa Lubb/f — Dr. Vanhoffen observed 
the luminosity on the head or neck, and on the abdomen over the furca. 
Sometimes the whole body seemed bluish. The living animal is colour- 
less, excepting two moss-green spots on the posterior part of the head, 
and sometimes other spots at the end of the abdomen. It is therefore 
likely that these are the luminous glands. 
Vertical Distribution of Lacustrine Crustacea.i — Prof. 0. Zacharias 
has paid particular attention to the autumnal distribution of Cyclops 
oithonoides. Towards autumn the vertical distribution becomes more 
uniform, and gradually the deeper strata show approximately the same 
numbers as those above. The microscopic plants of the surface are 
dying off, and sinking as a shower of nutritive particles, so that there is 
suitable food at all strata. 
Independence of the Paternal and Maternal Nuclear Substance in 
Early Stages of Development of Cyclops.§ — Herr J. Riickert maintains 
that in the early cleavages of Cyclops there is no mingling of the 
paternal and maternal halves of the nucleus, in at least some of the 
nuclei. The chromatin retains its original distribution in spite of 
repeated mitoses and active metabolism. The nucleus is symmetrically 
divisible into a paternal and a maternal half. 
Zoological Position of Trilobites.)) — Mr. H. M. Bernard, who has 
from time to time contributed technical memoirs on the much-disputed 
subject of the zoological position of the Trilobites, has a more popular 
article in which he summarises recent facts bearing on the problem. 
He thinks there is now ample evidence to demonstrate once for all the 
affinities of the Trilobites to Apus, as common derivatives of an annulate 
ancestor from which neither is far removed. 
Annulata. 
Generative Organs and Products of Tomopteris.^ — Dr. J. H. Ful- 
larton describes Tomopteris onisciformis Eschscholtz. The sexes are 
separate, the females much more numerous than the males. Testes 
* Boll. Soc. Entomol. Ital., xxvi. (1895) pp. 3-10 (8 figs.), 
f Zool. Anzeig., xviii. (1895) pp. 304-5. 
t Biol. Centralb]., xv. (1895) pp. 686-8. 
§ Arch. f. Mikr. Anat., xlv. (1895) pp. 339-69 (2 pis.). 
|| Science Progress, iv. (1895) pp. 33-49. 
II Zool. Jahrb. Abth. Anat., viii. (1895) pp. 425-46 (3 pis.). 
