146 SUMMARY OF CURRENT RESEARCHES RELATHSTG TO 



the yolk-granules are formed by the combination of a cytoplasmic con- 

 stituent with chromatin. The first yolk-granules appear within the 

 nucleus. A new nucleus is formed by a pseudo-contraction of the over- 

 laden old nucleus. This pseudo-contraction leads to the shedding of 

 some of the karyosomes, which function as yolk-nuclei. These yolk- 

 nuclei are stores of chromatin which continue the functional activity of 

 the nucleus of the growing primary oocyte. That is to say, their use is 

 to supply chromatin for that combination which results in yolk-forma- 

 tion. The ultimate oogonium is nourished by endosmosis, the primary 

 oocyte by the epithelium of the oviduct. In both cases the all- 

 important substance received is the cytoplasmic constituent, which enters 

 into yolk-formation. Chromatin constituents, however, must be derived 

 from without in the earliest stages. J- A. T. 



Annulata. 



Polychseta of Northern Coasts of Spain. — Enrique Rioja {Tra- 

 lajos Mus. Nac. Gienc. Nat. Madrid, Ser. Zool, 1918, 37, 1-99, 20 

 figs.). The 'author's report deals with eighty-one species of littoral 

 Polychasta, including ffyalinacia fauveli sp. n. and Nereis (Nean- 

 ihioides) boUvari sp. n. The latter is placed in a new sub-genus, including 

 those species of Nereis in which all the groups of paragnaths are com- 

 plete, those of the ventral basal portion of the proboscis being united in 

 a complete girdle. In the sub-genus Neanthes the groups of jjaragnaths 

 are also all complete, but those of the dorsal basal portion are distinctly 

 separate from one another and from those of the ventral portion. A new 

 variety of Glycera convoliita is based on a minute feature, the hooked 

 end of the aciculum of the ventral blade of the parapodia, which are 

 also more robust than in the type. J. A. T. 



Intercalary Growth in a Maldanian Worm. — P. Fauvel {Bull. 

 Soc. Zool. France, 1919, 44, 3G-40). In a strange Polychtete, Gra- 

 vierella multianmdata g. et sp. n., there is a remarkable proliferation. 

 The succession of segments in the abdominal region is interrupted by 

 the intercalation of a series of segments, the first few very rudimentary, 

 the others gradually increasing until the normal size is exhibited. This 

 was observed in a dozen cases. It recalls the proliferation in a tape- 

 worm and the stolonization of some Syllids. In one case there were two 

 proliferating zones widely separated. It may be a rapid method of 

 making good posterior breakages, or it may be the result of some 

 unknown irritation. J. A. T. 



Anabiosis in Earthworms. — Peter Schmidt {Journ. Exper. Zool.^ 

 1918, 27, 57-72). Earthworms subjected to exsiccation or desiccation pass 

 into a state regarded as analogous to the anabiosis of Tardigrada, 

 Rotifers, and Nematodes. They lose their mobility ; they shrink to one- 

 half or one-third of their length and volume ; they show no manifesta- 

 tions of life. No contractions were seen in the dorsal blood-vessel. The 

 capacity for revivification may be retained for thirty-nine hours in 

 summer, for forty-eight hours, and perhaps more, at low temperature. 



