518 SUMMARY OP CURRENT RESEARCHES RELATING TO 



gradual contractiou of the sperm-case forces tlie contents throngli the 

 skin in a steady stream, which can be seen under a magnifying power of 

 twenty diameters. 



Reproductive Organ of Phascolosoma Gouldii.* — Mr. E. A. 



Andrews has examined the reproductive organs of this Gephyrean. 

 There is a single reproductive organ, made up of a solid mass of germ- 

 cells supported by a structureless lamella projecting horizontally from 

 between the retractor muscle-fibres and the enveloping peritoneal mem- 

 brane ; it is invested by a delicate nucleated membrane. Branches of 

 the supporting lamella extend into the chief lobes of the organ, and are 

 accompanied by elongated nuclei, similar to those of the peritoneal 

 membrane. The germ nuclei have quite different staining properties 

 from these nuclei ; they increase in size towards the distal or free ends 

 of the lobes of the organ, where they are surrounded by protoplasm ; 

 this acquires definite cell-walls before the cells thus formed break loose 

 from the others into the coelom. In this last various stages in the 

 growth of the ova, from the naked cells, 24 yw, in diameter, to the 

 apparently mature, 185 /x in diameter, were observed. An ovum in 

 which the yolk measures 151 /a had a vitelline membrane 3 yu, thick 

 perforated by innumerable pores, through which delicate pseudopodia- 

 like processes pass out into an outer gelatinous case 12 [x thick. 



The reproductive organ of P. Gouldii is probably to be regarded as 

 a thickened fold of the peritoneum supported by a structureless basement 

 membrane or lamella; the nuclei of the peritoneum multiply rapidly to 

 form a mass of germ nuclei, which, on the surface of the mass, acquire 

 considerable cell-protoplasm ; they are then forced out from the ends of 

 finger-like processes into the coelom by the growth of more deeply 

 lying cells ; the investing membranous part of the original peritoneum 

 is ruptured at its ends, when this occurs. 



j3. Nemathelmintlies. 



Coffee-Nematode of BrazlLf — Dr. E. A. Goldi has a note on Meloi- 

 dogyne exigua, the nematode which has for nearly twenty years been the 

 cause of disease in the coffee-plantations of Brazil. The females are 

 found to form cysts in swellings on the plants, and their vegetative 

 organs are reduced, while their ovary is so swollen as to make the 

 recognition of the vermian nature of the formless sack a matter of diffi- 

 culty. The ova, which are 0*085 mm. long, have a transparent, thick 

 and resisting membrane. The young are transparent, colourless, and 

 cylindrical, the aboral end being drawn out to a long, fine point ; at the 

 terminal end of the cesophagus there is a spherical, muscular swelling. 

 Ttie adults are more club-shaped in form, the aboral end being thicker 

 than the oral, and ending in a sharp spine. A great deal remains to be 

 discovered with regard to the discrimination of the sexes, the manner in 

 which encystation is effected, and the wanderings of the yoiing. 



Physaloptera.J — Prof. M. Stossich gives an account of the general 

 characters, the constituent species, and the distribution of the Nematode 

 genus Physaloptera Rudolphi. Twenty-eight certain species already 

 recorded are diagnosed, and notice is taken of nine others insufficiently 



» Zool. Anzeig., xii. (1889) pp. 140-2. t Zool. Jahrb., iv. (1889) pp. 262-7. 

 X Bull. Soc. Adriat. Sci. Nat., si. (1889) pp. 30-59 (B pis.). 



