610 SUMMARY OF CURRENT RESEARCHES RELATING TO 
backwards, but leaving a series of bridges segmentally arranged. 
Cavities appear in tbe hypochorda, and sections show that in the anterior 
trunk segments the hypochorda is made up of segmental tubes which 
rise dorsally from the gut and then bend caudalwards. This suggests 
the hypothesis that the hypochorda may have arisen from - the union of 
a series of segmental evaginations. After the cavities have appeared 
complete constriction from the gut occurs, the aorta arises between, 
and the elements atrophy, flatten, and disappear, without taking any 
part in forming the spleen or leucocytes. 
Behind the dorsal rudiment of the pancreas there appears in the 
eighth myomere a second process. This is the root of the Schwanzdarm , 
and has nothing to do with the pancreas or any other organ. The 
author suggests that this may be the nature of the alleged fourth rudi- 
ment of the pancreas in the sturgeon, but with this von Kupffer does 
not agree. 
Influence of Chloride of Lithium on the Development of the Eggs 
of the Frog and the Toad.* — Herr A, Gurwitsch finds that the influence 
of lithium chloride on the eggs of these two Amphibians is so similar 
that one description will do for them both. Comparing his results with 
those of Herbst on eggs of Echinoids, he comes to the conclusion that 
the influence of lithium salts has some connection with the reabsorption 
of yolk-granules in the large yolk-cells. 
Development of Branchial Skeleton in Ammocoetes.f — Herr C. v. 
Kupffer finds that the cartilage does not arise within the mesodermie 
arches, nor from cells derived from these, but from and within the ecto- 
dermic epithelium which lines the whole branchial region, the branchio- 
dermis. This raises the question of the homology between the branchial 
cartilages of Petromyzontidse and the gill-arches of Amphirhini; the 
former are external, the latter internal. And what of the outer arches 
of Elasmobranchs, do they form a third category ? But the chief result, 
that the branchial skeleton in Ammocoetes is cutaneous, leads to the 
conclusion, of which there has been recently other evidence (Gorono- 
witsch, Platt, Klaatsch) that the role of the ectoderm has been too 
hastily restricted. 
/3. Histology- 
The Cell Theory.^ — Mr. G. C. Bourne has prepared an answer to 
Mr. Sedgwick’s article on the inadequacy of the cellular theory of 
developments He urges at the commencement that while Mr. Sedgwick 
asserts that there is a want of precision about the cell-phantom, there 
is a considerable amount of vagueness in Mr. Sedgwick’s method of 
propounding his own views. While doing his best to understand them 
he asks pardon if he has misinterpreted them. He shows cause for 
the view that there is very slender ground for the accusations which 
Mr. Sedgwick levels, in an unsparing manner, against his zoological 
contemporaries. He urges that the phenomena to which Mr. Sedgwick 
draws our attention have received their due amount of recognition from 
* Anat. Anzeig., xi. (1895) pp. 65-70 (5 figs.), 
f Verb. Anat. Ges., ix. pp. 105-22 (7 figsA 
1 Quart. Journ. Micr. Sci., xxxviii. (1895) pp. 137-74. 
§ See this Journal, ante , p. 29. 
