ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 4'. I 



The dorsal gland is temporary, and disappears when the larva abandons 

 its pelagic habits and begins to construct its sandy tube. The larvae 

 were found to possess three separate pairs of nephridial ducts withoui 

 nephrostomes, but the relation of these larval nephridia to those of tin- 

 adult was not determined. 



Protandry in Grubea.*^<;. Du Plessis has studied Grubea protan- 

 ilrka sp. n., one of the Syllids, which is neuter in summer, male in 

 -autumn and winter, and female in spring. In April, after the b 

 have disappeared, there is a short period during which there are ripe 

 spermatozoa in the testicular segments, while ova are being formed in 

 all the posterior segments. 



Polyspermy in Protula meilhaci.t — A. Soulier finds that poly- 

 spermy is not infrequent in this Annelid ; several spermatozoa unite with 

 the female pronucleus, acting as kinetic centres and giving rise to 

 multipolar figures. The chromatin of the ovum is distributed in frag- 

 ments in the cytoplasm. Eggs that exhibit this degenerate. Inartificial 

 fertilisation all the eggs may fall victims to polyspermy. Lack of oxygen 

 seems to favour it. 



Giant Nerve-cells of Halla.t — J. H. Ashworth describes the giant 

 cells which occur in segmental couples in each of the anterior ganglia 

 of Holla parthmopeia. Each giant fibre, after leaving the giant cell 

 from which it arises, crosses the cord to the opposite side, turns gradually 

 towards the middle line of the cord, and runs posteriorly. The neuro- 

 fibrillar network in the giant cell is divisible into a perinuclear, situated 

 at the margin of the perinuclear zone, and a more extensive, wider 

 meshed, and generally more slender-stranded network in the general 

 protoplasm. In Aglaurides fulgida similar giant cells and fibres are 

 found. 



Regeneration in Saccocirrus.§— Aug. Michel describes the growth 

 of an anterior bud from the injured head-end of the primitive Annelid, 

 Saccocirrus papillocercus. The bud showed eyes and antenna?, and hints 

 of six segments. After two weeks there was a regulative reduction of 

 antennae and segments, and a ganglionic rudiment appeared. 



Regeneration in Spirographs spallanzani.|| — P. Ivanov found 

 that pieces of the abdominal region, or of the abdominal and thoracic 

 regions together, regenerated the missing ends. At the posterior end a 

 pvgidium grows which gives rise to a large number of new abdominal 

 segments. At the anterior end a primordium is formed which differ- 

 entiates into four segments : the mouth-segment, the collar-segment, and 

 the two first setiferous segments (making the prothoracic region in all i. 

 By a partial change in the six most anterior of the old segments, the 

 posterior thoracic region is formed. 



The results go to show that the prothoracic segments of the sedentary 



* Rev. Suisse Zool., xvi. (1908) pp. 321-8 (1 pi.). 



t Arch. Zool. Exper., ix. (1908) Notes et Revue, No. 3, pp. lm.-lv. 



% Proc. Roy. Soc., Series B, lxx. (1903) No. B 543, pp. 463-4. 



§ Comptes Rendus, cxlvii. (1908) pp. 1005-6. 



|1 Zeitschr. wiss. Zool., xci. (1903) pp. 511-58 (3 pis. and 2 figs.). 



Feb. 17th, 1909 E 



