ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 255 



ground which the creatures frequent, but on stony or rocky ground 

 covered with shells. It is suggested that the adults cease to feed 

 when sexually mature, but the basis of certain fact remains very narrow. 



Blastoderms without Embryos.* — G. Loisel distinguishes (a) those 

 cases in the development of the fowl's egg where the blastoderm having 

 begun to form an embryo is arrested in this respect, and (6) those in 

 which there is no hint of embryonic development. In the latter there 

 has been no fertilisation of the female pronucleus by the sperm-nucleus, 

 but the blastoderm may proceed to grow over the yolk, from an equa- 

 torial band towards the pole — the inverse of the opposite direction. 

 The author suggests that the zoual blastoderm is due to vagrant sperma- 

 tozoa which have lodged in that region, and have multiplied partheno- 

 genetically at the expense of the reserves of the egg. 



Merogony and Ephebogenesis.j — Prof. Th. Boveri points out that 

 these two terms, invented by Delage and Rawitz respectively, are new 

 names for an old discovery. He refers to his papers of 1889 and 1895, 

 and to the criticisms of Verworn, Morgan, and Seeliger, which he thinks 

 Delage has misrepresented. He seeks to vindicate his original position. 



Influence of Saline and Saccharine Solutions on Frogs' Eggs.J — 

 Madame Rondeau-Luzeau has observed that eggs of Bana fusca im- 

 mersed for two hours in equi-osmotic solutions of NaCl 1 p. a, and of 

 sugar 10 p.c, show similar effects. The superficial aspects of a four-cell 

 stage are seen on some, but usually there is a very irregular apparent 

 cleavage of the upper hemisphere. There is no evidence of nuclear divi- 

 sion ; the effect is wholly physical. The egg seems much more affectable 

 before fertilisation than afterwards. After fertilisation, solutions of 

 CaCl 2 , 1*4 per 100, allow the formation of moruk-e ; solutions of NaCl, 

 1 per 100, kill the egg at the four-cell stage ; sugar solutions, 10 per 

 100, have no marked influence until the closure of the blastopore, which 

 is a very critical moment. 



ArtificialJIncubationiof Alligator Eggs. § — A.M. Eeese records an 

 unsuccessful and a successful attempt to hatch the eggs of the Florida 

 alligator. In the first case, the eggs only survived for about a week y 

 although the temperature range was only from 32° G. to 4.0' C. ; in this 

 experiment the eggs were placed in an artificial nest which was exposed 

 to the sun by day, and brought into a closed room at sunset. In the 

 successful exrjeriment the eggs were kept in an incubator at 37° C, and 

 after a fortnight the contained young began to make the squeaking 

 sounds believed to act as a warning to the mother. The sound was 

 audible at a distance of over 15 yards. At hatching, the young are 

 20 cm. in length. 



Lecithoblast and Angioblast in Vertebrates.|| — Prof. W. His, under 

 this title, discusses some general points connected with yolk, yolk-ab- 

 sorption, and germ-layers in the different groups of Vertebrates. In 

 developing meroblastic eggs, there can be distinguished the organised 



* Comptes Kendus, exxxii. (1901) pp. 350-3. 



t Anat. Auzeig., xix. (1901) pp. 156-72. 



j Comptes Kendus, exxxii. (1901) pp. 997-9. 



§ Amer. Nat., xxxv. (1901) pp. 193-5. 



|| Abth. k. Sachs. Ues. Wiss., xxvi. (1900) pp. 173-328 (102 figs.). 



