ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
287 
Post-Larval Fierasfer.* — Prof. W. C. McIntosh describes a post- 
larval stage of this interesting fish, captured by Miss Delap at Yalentia, 
on the south-west coast of Ireland. It probably belonged to Fierasfer 
acus, a form not hitherto known off British coasts. 
Metamerism of Head in Torpedo. f —Herr A. N. Sewertzoff finds 
that the Squaloid head ( Pristiurus , &c.) and the Batoid head (Torpedo) 
are segmented after the same type. He concludes that the occurrence 
of more segments in the Batoid head is secondary, and is probably associ- 
ated with the general shortening of the body. 
Copulation in Ophidians.^ — R. Rollinat gives a preliminary account 
of egg-laying and copulation in Tropidonotus viperinus. The species 
appears in March and disappears in November, passing the winter in a 
hole. The eggs are laid in June or July, and the young hatched in 
September or October. Rollinat invariably found that the oviducts of 
females which had already laid eggs contained abundant living sperma- 
tozoa in November, while those of females of full size whose organs 
showed no trace of previous egg-laying, contained none. He concludes 
that in fully mature females copulation takes place before the hibernating 
period, and not in March or April as has hitherto been supposed. In 
females laying for the first time, copulation probably takes place in 
early spring. 
In Goronella Isevis , a less common ovoviviparous species, pairing 
occurs very shortly after egg-laying ; in Vipera aspis in March. 
Sex and Molecular Dissymmetry.? — M. Felix le Dantec hazards the 
hypothesis that some of the plastic substances of the germ-cells have 
dextral and sinistral (dissymmetrical) molecules, and that the sex of the 
offspring depends on the preponderance of the one or the other under 
the influence of nutritive and other stimuli. M. Edmond Perrier appends 
some account of recent observations bearing on the determination of 
sex. 
Variations in Weight of Hens’ Eggs.]] — Dr. Ch. Fere has weighed 
over a thousand eggs, the average being GO grammes. The number 
weighed was not sufficient to warrant a conclusion ; but so far as the 
statistics go, they suggest (1) the inferiority in weight of the first egg in 
a laying, and (2) a progressive increase in mean weight in successive 
layings. 
Convergence in Development.^]* — Dr. Karl Peter has studied the 
structure and development of the chondrocranium, and the subsequent 
formation of the skull in Ichthyophis glutinosus , one of the “ blind worms.” 
His general result is of much interest, that almost every peculiarity in 
the skull of Ichthyophis , which makes it divergent from that of the 
Urodele-type, is also seen in the skull of AmphisbasnidEe. The re- 
semblance is often very striking. He concludes that the deviations are 
not expressions of old-established characters, but are adaptive phenomena. 
* Irish Naturalist, vii. (1898) pp. Gl-4 (1 pi.), 
f Anat. Anzeig., xiv. (1898) pp. 278-82. 
X Bull. Soc. Zool. France, xxiii. (1898) pp. 59-63. 
§ Comptes Rendus, exxvi. (1898) pp. 26!-7, 267-72. 
(i Journ. Auat. Physiol., xxxiv. (1898) pp. 123-7 (1 fig., curves). 
Morphol. Jahib.,’ xxv. (1898) pp. 555-628 (3 pis. and 1 fi°\). 
1898 
x 
