404 SUMMARY OF CURRENT RESEARCHES RELATING TO 



and the median vaginae, all remain imbedded in the genital cord, and so 

 retain the position occupied by the Miillerian ducts in the foetus. 

 Further in both animals there is a distinct cloaca. The organs of 

 Myrmecobius differ from those of Perameles in that the middle parts of 

 the lateral vaginae are free and coiled, and in that there is a long urino- 

 genital sinus. The author has further re-examined Trichosurus vulpecula, 

 and corrects his previous statement that parturition here takes place 

 through the lateral vaginal canals. He now finds reason to believe that 

 a pseudo-vaginal passage is formed during birth, and as in Perameles: 

 rapidly disappears after birth, to be formed anew at the next parturition. 



Development of Ductus Endolymphaticus.* — Dr. B. Erause has in- 

 vestigated a large series of Vertebrate embryos, in order to confirm or 

 disprove Balfour's statement that the ductus endolymphaticus of higher 

 forms is the homologue of the duct found in the Elasmobranchs, and 

 therefore the remnant of the original invagination which forms the ear. 

 He is able to entirely confirm Balfour's view in birds, reptiles, and 

 mammals, and finds further that no true ductus endolymphaticus exists 

 in fishes. 



Artificial Rearing of Soles.f — Fabre-Domergue and E. Bietrix note 

 that they have succeeded in rearing soles from the egg to the assumption 

 of the adult form. This has been done iu four other cases, — herring 

 (Meyer), Gottus (Fabre-Domergue and Bietrix), plaice (Dannevig), and 

 blenny (Garstaug). 



The young soles first fed on plankton-organisms ; when their yolk- 

 sac was exhausted they devoured larval fishes ; when the adult form was 

 assumed they ceased to hunt for larval fishes and turned to Copepods 

 and small Annelids. In May some of the young soles had reached a 

 length of 35 mm. The authors succeeded with about 50 per cent., and 

 they suggest the practical importance of their experiments. 



Development and Significance of the Ora Serrata. $— Prof. 0. Schultze 

 finds that this characteristic structure of the human eye is merely a 

 result of the conditions of development, and has no functional importance. 

 At the time when the ciliary processes begin to raise themselves from 

 the primitively smooth surface of the corpus ciliare, the retinal invest- 

 ment of the last-named, originally very thick, becomes gradually thinned. 

 The thinning process spreads over the optic cup as the ciliary body be- 

 comes differentiated, and its posterior margin forms the ora serrata. The 

 jagged nature of the ora serrata is due to the formation of projections 

 and hollows as the ciliary processes spread backwards, and the fusion or 

 partial disappearance of these gives rise to the variable conditions found 

 in the adult. 



b. Histolog-y. 



Blood-Circulation without Capillaries. § — Prof. Charles Sedgwick 

 Minot brings forward evidence to show that in all Vertebrates there 

 occur two types of blood-vessel with endothelial or endothelioid walls 



* Anat. Anzeig., xix. (1901) pp. 49-59 (21 figs.). 



t Coinptes Kendus, exxxii. (1901) pp. 113G-8. 



j Verb. Phys. Med. Ges. Wiirzburg, xxxiv. (1901) pp. 131-43 (1 pi. and 3 figs.). 



§ Proc. Boston Soc. Nat. Hist., xxix. (1900) pp. 185-215 (12 figs.). 



