426 RECORD OF CURRENT RESEARCHES RELATING TO 



female generative openings, one on each side of the ventral surface of 

 the fifth body segment. Each opening leads into a receptaculum 

 seminis, which is formed of a thin chitinous membrane, invaginated 

 into the oviduct, and completely closing it, so that it was equally 

 difficult to understand either how the ova could be fertilized, or how 

 they could pass out. 



Some days after the receptacula seminis have been distended by 

 copulation, they burst and set free the spermatozoids into the oviduct. 

 These at first form a coil at the top of the duct, but soon press into 

 the ovary, disperse themselves through it, and so fertilize the eggs. 



About this time the female casts the posterior half of her chitinous 

 integument, beginning with the fifth body segment, and in a few days 

 more the anterior portion also. The ecdysis is attended with so much 

 pain and difficulty that many females die of exhaustion. The new 

 skin is continuous over the mouth of the oviduct, the female genera- 

 tive openings and receptacula seminis are lost, and the latter is repre- 

 sented by a mere filament of chitin lying along the closed oviduct. 

 The author's hypothesis of the alternate presence and absence of the 

 disputed organs was completely verified. 



The new integument bears a pair of large overlapping broad plates 

 on each of the first five body segments, thus providing a large pouch 

 for the development of the eggs. These now descend the oviduct, but 

 on arriving at its blind end break loose into the body cavity, and 

 escape into the brood-pouch through a broad median slit in the chitin- 

 ous integument of the sixth body segment. The ovary then shrivels, 

 and any unfertilized ova degenerate and disappear. The irregularly 

 scattered residual spermatozoa return into the oviduct, and there wind 

 themselves neatly into a somewhat spectacle-shaped bundle. A new 

 development of ova from the epithelium of the ovary soon commences, 

 and in about twenty-three days after the first batch of eggs left the 

 ovary a new set are distinctly formed. These continue growing for 

 twenty to twenty-six days more, by which time the first brood is hatched 

 and set free. The spermatozoa then arouse and uncoil themselves, re- 

 enter the ovary, and fertilize the ova, which then pass into the brood- 

 pouch by the median slit already mentioned. Thus one act of 

 fertilization serves for two broods, a circumstance which Dr. Schobl 

 thinks may throw new light upon many of the supposed cases of par- 

 thenogenesis. 



That the spermatozoids of Isopods are not inert and motionless is 

 further proved by direct microscopic observation of freshly-shed speci- 

 mens. Not only have they a movement of rotation around their own 

 axis, but they are capable of slow locomotion. 



In autumn the skin is again cast ; the broad plates are then lost, the 

 genital openings and receptacula seminis are recovered, and the animal 

 is ready to be fertilized anew. 



Filiform Laemodipoda.* — Dr. Heller seems to have enjoyed pecu- 

 liar facilities on the Italian and Sicilian coasts for his work on the 

 Caprellidae, since he not only gives a detailed account of their aua- 



* 'Zeitschr. wiss. Zool.,' xxxiii. (1879) p. 350 (3 plates). 



