ZOOLOGY AND BOTANY, MICROSCOPY^ ETC. 65 



possessors are also studied. The essay now before us may be taken as 

 a biological supplement to the author's essay on the gills of the 

 Serpulacece* 



The simplest coloration among the SabellidfB obtains in Myxiola ; 

 it is more varied in BrancMomma, and still more so in SpirograpJiis. 

 In all these, however, the colours are sober. In Serpula they are 

 brighter. As it is almost certain that these colours have no sexual 

 significance, and hardly appear to serve as a means of defence, and as 

 different shades of light or darkness seem to have no influence on the 

 worms, we are led to inquire if they have no relation to respiratory 

 phenomena. The Serpulacese are often found living in places poor 

 in oxygen, and the pigments are only developed in such parts of 

 their bodies as are exposed to a rich supply of water ; for example, 

 the tubicolous Praxilla has the fore-end of the body of a bright red 

 colour, but the hinder part is colourless. The author recognizes the 

 necessity of chemical investigations and of studies which shall be 

 more complete from a physiological point of view. 



Lower Animals of the Bay of Algiers.^ — The first annelid dis- 

 cussed by C. Viguier is Exogone gemmifera, on which he published a 

 short note in 1883 ; J as with this, so with the others, Sphcerosyllis 

 pirifera, Syllides pidliger, and Gruhea limhata, especial attention was 

 directed to the process of gestation. The chief results arrived at are 

 (1) that we cannot di-aw useful arguments from the presence or absence 

 of capillary setae in determining the sexual or asexual condition of 

 the worms ; (2) that the position of the ova or the larvae is not constant in 

 the procreating females of the Syllidae ; for while they are ventral in 

 Exogone and Sphcerosyllis, they are dorsal in Syllides and Gruhea ; and 

 (3) the history of development may differ remarkably in species which 

 are very closely allied to one another ; for example, the envelope of 

 the ovum becomes the cuticle of the larva in Exogone and Syllides, 

 while it is cast off in Gruhea. The author particularly combats the 

 views of Pagenstecher, and believes that his observations are far from 

 confirming the results of that naturalist. 



Metamorphosis of Filaria sanguinis hominis in the Mosqiiito.§ 

 — Dr. P. Manson gives a full account of the metamorphosis under- 

 gone by the embryo of Filaria sanguinis Jiominis in the body of the 

 mosquito, and finds the results of his previous researches || fully 

 confirmed. 



Structure of Rotatoria.lf — L. Plate finds that in the genital 

 organs of the female, the so-called ovarian nuclei in the ventral sac 

 of the cloaca are more properly to be considered as forming the 

 yolk, the true ovary being discovered in a small mass of multinucleate 

 protoplasm lying close to the yolk-mass [Dotter stock). The develop- 



* See this Journal, iv. (1884) p. 745. 



t Arch. Zool. Espe'r. et Ge'n., ii. (1884) pp. 69-110 (3 pis.). 



I See this Journal, iii. (1883) p. 371. 



§ Trans. Linn. ?oc. Lond, (Zool.), ii. (1884) pp. 367-88 (1 pi.). 



II Proc. Linn. Soc, 7th March 1878. 



1[ Zool. Anzeig., vii. (1884) pp. 573-6. 

 Ser, 2.— Vol. V. F 



