182 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Development of Epiphysis in Reptiles.* * * § — Prof. E. Bugnion has 
studied this in Iguana , Lacerta , and Coluber , and finds that the epiphysis 
has not a separate origin from the parietal organ. The epiphysial 
diverticulum arises dorsally in front of the posterior commissure, and 
forms distally the parietal organ, which is gradually detached. The 
nerve destined for this organ is formed, not in the stem of the epiphysial 
diverticulum, but on a small swelling of the ganglionic wall in front of 
the latter. The so-called paraphysis is a simple epithelial structure in 
connection with the choroid membrane and its plexus. 
Some Activities of Polar Bodies, j — Prof. E. A. Andrews remarks 
that the acceptance of the view that polar bodies are but imperfect ova 
incapable of fertilisation and without any role in development, has 
naturally tended to lessen interest in their fate. Yet their behaviour 
after extrusion shows some interesting phenomena. He has studied 
those of Asterias , Cerebratulus, the nudibranek Tergipes , the lamelli- 
branchs Nucula and Angulus , and other forms. He finds that the polar 
bodies in these cases (representative of Echinoderms, Nemertines, and 
Molluscs) show marked activities, chiefly of an amoeboid nature. In 
some cases the polar bodies behave like Heliozoa. They may also 
remain vitally connected with one another, and with the developing 
embryo for some time after extrusion. “ How far these phenomena are 
normal, and how much may prove to be pathological, cannot be at 
present decided ; but, in any event, it has been shown the protoplasm of 
polar bodies has powers hitherto unsuspected.” Perhaps the last word 
should rather read “ undescribed,” or “ inadequately described.” 
Pronephros of Lamprey .+ — S. Hatta gives a preliminary account of 
his observations on the development of the pronephros in the lamprey. 
These lead to the following conclusions : — Both the pronephric tubules 
and the segmental ducts are purely organs of the lateral unsegmented 
portion of the mesoblast. The Anlagen of the tubules follow the same 
segmental arrangement as the mesoblast somites. The maximum num- 
ber of pronephric tubules is six pairs, of which the first, second, and 
sixth degenerate one after the other. The persistent tubules are, there- 
fore, the third, fourth, and fifth, of which the third pair is not so well 
developed as the next two. The first and second pairs originate in the 
region where the gill-slits are afterwards formed, and they disappear as 
the slits arise. 
The facts closely agree with Price’s observations on Bdellostoma , 
and there is strong reason to believe that the pronephros of Cyclostomata 
is homologous with Boveri’s Nierencanalchen in the lancelet, and that the 
persistent tubules of the lamprey are homologous with those of Selachii, 
Teleostei, Amphibia, &c. 
Egg-laying of Dog-fish.§ — Herr Fr. Kopsch has studied the egg- 
laying of Scyllium canicula in the aquarium at Rovigno. The chief 
spawning time seems to be from the beginning of March to the end of 
* Arch. Sci. Phys. Nat., cii. (1897) pp. 489-90. 
t Ann. Mag. Nat. Hist., i. (7th series) 1898, pp. 109-116 (5 figs.). Johns 
Hopkins Univ. Circ., 1897, pp. 14-16. 
% Annot. Zool. Japon., i. (1897) pp. 137-40. 
§ Biol. Centralbl., xvii. (1897) pp. 885-93 (3 figs.). 
