484 SUMMARY OF CUliRENT RESEARCHES RELATING TO 



membrane is broadly produced, the peduncle of the second antenna is 

 elongate, the mandibles are narrow, the first maxillae are developed, the 

 pleopods have fringes of seta^, and the telsonic segment is narrowly 

 produced to a sharp point. A new family Thambematidae is estal)lished 

 for Thamhema amicorimi g. etsp. n. from the west of Ireland. The 

 most remarkable featui'e is the consolidation of all the segments of the 

 pleon ; the pleopods do not exceed four pairs, the missing pair being 

 probably the fifth ; the second antennae are seemingly imperfect ; the 

 last three pairs of perseopods have lost all the structure following the 

 second or basal joint. 



Study of Asellus aquaticus.* — Georg J. v. Kaubersz has made a 

 number of interesting observations and experiments especially as regards 

 regenerative capacity and sensory structures. Only a few points can be 

 referred to. An ecdysis of the female always takes place after the com- 

 pletion of copulation. There is a partial regeneration of the olfactory 

 antennae. The animals are negatively phototropic. The skin is not 

 insensitive to light, but the eyes are of chief importance. Visual powei' 

 is poorly developed. The olfactory clubs on the olfactory antennae are 

 described. It seems that the chemo-receptors are chiefly, though not 

 exclusively, the first antennae. The slightest disturbances in the water 

 are perceived by the feathery setee, even at a distance of several centi- 

 metres. Minute details are given as to the structure of the antennae. 



Reproduction of Amphipods.t — Gr. C. Embody has made some in- 

 teresting observations on Gammariis fasciatus^ G. limnseus,Eucrangonyx 

 gracilis^ and Hyalella hikkerhockeri The average number of eggs 

 deposited at one time is 22, 25, 45, and 18 for the above species in the 

 order given. The males of Gammarus Ihmiseus^ G. fasciatus, and 

 Hyalella, may mate with females even Avhen the latter carry eggs or 

 young in the brood-pouches. The males separate permanently from their 

 mates immediately after semination. The period of incubation varies 

 inversely as the temperature of the water, but not in a constant ratio. 

 It is quite probable that all the eggs of G. limnseus hatch in not less than 

 18 days after oviposition. The young Amphipods remain in the brood - 

 pouch during a period varying from 1 to 8 days ; but during this period, 

 in Eucrangonyx gracilis at least, the young may have gone out and in 

 again several times. The recurrence of oviposition follows closely the 

 recurrence of ecdysis. The young of E. gracilis grow slowly as compared 

 with the other three species named, and probably do not reach maturity 

 until the second year. The young of the others mature and reproduce 

 many times during the first year. 



New Amphipod from Transvaal. j:^ — Paul A. Methuen describes 

 Talitriator eastwoodse g. et sp. n., from streams in the Woodbush, 

 Northern Transvaal^ — the first Gammarid recorded from the fresh-waters 

 of South Africa other than near the sea. It is very closely related to 



* Zool. Jahrb., xxiii. (1913) pp. 287-360 (2 pis. and 13 figs.). 



t Internat. Rev. Hydrobiol., Biol. Suppl., ser. 3 (1912) pp. 1-33 (1 pi.). 



: Proc. Zool. Soc, 1913, pp. 109-12 (2 pis.). 



