20 SUMMARY OF CURRENT RESEARCHES RELATING TO 



mounds on the hand than on the foot in the foetus, the "centres of dis- 

 turbance " occur on the foot more frequently than on the hand in the 

 adult. 



Cerebral Outgrowths in Geckos.* — Herr F. Melchers reaches the 

 following conclusions. The epiphysis in Plaiydactylus is a simple 

 median intrameningeal evagination of the roof of the thalamencephalon, 

 pear-shaped, and with a solid stalk in adults. The paraj)hysis appears 

 later, as a long permanently hollow sac, with an often branched blind 

 end which lies in front of the epiphysis. Both are at a certain stage of 

 embryonic life visible externally, and may once have been sensory. In 

 the young animal both become vascularised, the epiphysis degenerates,, 

 and tbe paraphysis acquires a glandular appearance. The hypophysis 

 appears before either of the preceding, and Las a double origin as an 

 evagination from the brain, combined intimately with a pharyngeal in- 

 vagination. The orohypophysis is constricted off, and forms little buds 

 like the parapbysis. The neurohypophysis becomes a long irregular 

 vesicle. No present function can be stated. 



Origin of Sexual Reproduction.! — Prof. O. Lignier seeks to show,, 

 from studies on the Algae in particular, that tbe origin of fertilisation is 

 to be found in its utility as a source of variations which form tbe raw 

 material of adaptation, and, furthermore, that the dimorphism of the sex 

 elements is an adaptation on the one hand (in the ovum) to providing 

 the necessary nutritive material for early development, and, on the other 

 hand (in the spermatozoon), to securing conjugation. 



Female Urogenital Organs of Perameles.J — Mr. J. P. Hill describes 

 these organs in detail. Contrasted with those of other Marsupials, e.g. 

 Macropus, the following features stand out as worthy of remark : — 



(1) The absence of any sharply marked separation between the 

 uterine and vaginal segments of the organs, the uterus being directly 

 continued into the median vaginal cul-de-sac, and its os being extremely 

 ill-defined. 



(2) The small size and distinctness, in the virgin, of the median,' 

 vaginal cul-de-sacs ; their termination at a relatively great distance from 

 the urogenital sinus ; and their complete investment by the connective- 

 tissue of the urogenital strand. 



(3) The fact that the lateral vaginal canals (except their forward 

 expansions— the vaginal caeca) are imbedded throughout their whole 

 extent, together with the urethra, in an elongated mass of connective- 

 tissue, the urogenital strand. 



(4) The extremely short sinus urogenitalis, and the existence of a 

 very distinct cloaca. 



Features (1) and (4) constitute obvious marks of lowly organisation. 

 As regards (2), the median vaginal apparatus in Perameles remains at a 

 stage which is early passed over in the foetal Macropod, and is without 

 doubt extremely primitive. As concerns (3), the urogenital strand of the 

 adult is nothing else than the persistent genital cord, from the tissue of 



* Zeitschr. f. wiss. Zool., lxvii. (1899) pp. 139-66 (2 pis.). 



f Miscellanees Biologiques, Station Zoologique de Wimereux, dediees au pro- 

 fesseur Alfred Giard, 1899, pp. 396-401. 



X Proc. Linn. Soc. N.S. Wales, xxiv. (1899) pp. 42-82 (12 pis. and 3 figs.). 



