NOTES AND MEMORANDA. 291 



Development of Chaetopoda. — The development of two species of 

 Serpula (S. uncinaia and S. glomerata) i.as been studied by Michael 

 Stossich,* who sums up the results of his investigations as follows : — 



1. The eggs of tube- worms undergo comi^lete yolk-division. 



2. From the blastula a gastrula is formed by invagination: the 

 so-called blastopore passes directly into the permanent anus. 



3. The cleavage cavity (blastocele) is filled with an albuminous 

 or fatty fluid, exuded from the blastoderm-cells, which serves the 

 purpose of a food-yolk. 



4. The inner wall of the alimentary canal and the surface of the 

 free-swimming larva are covered with cilia. 



5. On the inner surface of the digestive canal are found two dupli- 

 catures marking the boundaries between CESophagus, stomach, and 

 intestine. 



6. The cleavage cavity undergoes conversion directly into the body 

 cavity, in which, probably, at a later period, the mesoderm cells arise. 



7. Above the anal aperture a vesicle (?) is formed, which is con- 

 nected with the formation of the muscular system. 



8. Underneath this " anal vesicle " the larv£e develop, at the end 

 of the body, a tongue-shaped mass, by means of which they attach 

 themselves to foreign bodies. 



Parasitism of Notommata on Vancheria.— E. Wollny, of Nieder- 

 lossnitz, has made some recent observations on the mode in which 

 this Eotifer is developed within the Vaucheria-cell. f The Vaucheria 

 in which the development takes place is so weakened as to be unable 

 to produce the reproductive organs ; the part in which the ova are 

 found being modified'for the purpose of forming the swellings or galls 

 within which the rotifer is developed from the ovum. The ova have 

 the tendency to force themselves into the Vaucheria-tube through the 

 canal which unites the gall to the tube, and do not escape directly 

 from the gall. The tube either then decays in consequence of being 

 deprived of nutriment, or the young rotifer forces its way through it. 

 In a Vaucheria obtained from Kome, Wollny detected also galls of a 

 slightly different character ; but he had no opportunity of examining 

 either the ova of the parasite or the perfect animal. 



Kidney of the Fresh- water Crayfish. — An investigation on the 

 curious " green-gland" of the Crayfish has been lately made by 

 C. E. Wassiliew, I whose observations form an important contribution 

 to our knowledge of that organ. He states that the gland consists of 

 a single unbroken coiled tube, blind at one end, opening at the other 

 into the sac of the gland or urinary bladder, and consisting of three 

 distinct portions. The first of these has the form of a somewhat 

 triangular yellowish-brown lobule, lying on the upper surface of the 

 gland and forming the blind terminal portion of the whole tube ; the 

 second forms a green cake-shaped mass, constituting the lateral and 

 inferior parts of the gland ; while the third is a long, white, coiled 



* ' Wiener Sitzungsb.,' Ixxvii. (1878) 1 Abth. 533. 

 t ' Hedwigia,' xvii. (1878) 5 and 97. 

 X ' Zool. Anzeiger,' i. (1878). 



u 2 



