290 SUMMARY OF CURREN r RESEARCHES RELATING TO 



show amitotic division, which is associated with the lobed character of 

 the nuclei and is not a multiplicative division. 



New Species of Gammarus.* — E. W. Sexton describes Gammarus 

 chevreuxi sp. n., from Chelson Meadow, near Plymouth. It resembles 

 G. locusta more nearly than any of the other species of the genus, but there 

 are certain constant characters, e.g. in the antennae, the fourth side- 

 plates, the third uropods, and so on, which appear to justify its establish- 

 ment as a separate species. 



Observations on Gammarus chevreuxi. f — E. AV. Sexton and Annie 

 Matthews have reared five generations in the artificial environment of 

 laboratory conditions. They describe the reproduction, which occurs 

 once a fortnight ; the moulting of the female, which is followed by 

 fertilization and oviposition; the young in the incubatory pouch and 

 after extrusion. 



Aberrations in Phyllopods.j: — E. Daday de Dees describes a variety 

 of Lynceus 'brachyuras^ in which the two sexes are identical, instead of 

 being dimorphic, as regards the characters of the rostrum. In Lyn- 

 celopsis perrieri g. et sp. n. he describes " andropleurodimorphism " ; 

 that is to say there are dextral and sinistral males as regards the first 

 two pairs of limbs. In a subsequent paper § the author describes 

 Chirocephalus sJcorikowl sp. n., Branchipus Iwuicornis sp. n., and some 

 other interesting forms. 



Parasitic Copepods on Alpine Whitefish.|l— F. Baumann describes 

 from various species of Goregonus three species of Copepod parasites — 

 Ergasilus surhecki sp. n. (in the family Ergasilidse), Acktheres coregoni 

 sp. n., and Basanistes coregoni Neresheimer (both in the family Lernfe- 

 opodidge). The Alpine whitefishes must be regarded as glacial relicts, 

 and there is an interesting northern character about Ergasilus surhecki. 

 As for the other two, it may be said, at least, that their nearest relatives 

 infest fishes which frequent cold water. 



Species of CycIops.1[^ — R. Neubaur has made a most careful com- 

 parison of Gyclops fuscus (Jur.), G. alhidus (Jur.), and G. distinctus 

 (Rich.), discussing sixty-seven characteristics in which the three species 

 differ, or in which two differ from the third. It is supposed that 

 G. distinctus arises from the hybridization of the other two species. It 

 agrees in two characteristics with G. fuscus and approaches it in nine ; 

 it agrees with G. alhidus in five and approaches it in eight ; in twenty- 

 one features it is intermediate : in fifteen features it shows a quantita- 

 tively excessive position ; in seven characters its position is isolated. 

 The general impression is that G. distinctus may owe its special character 



* Journ. Marine Biol. Assoc, ix. (1913) pp. 542-5 (5 figs.), 

 t Journ. Marine Biol. Assoc, ix. (1913) pp. 546-56. 

 I Ann. Sci. Nat. (Zool.) xvii. (1913) pp. 196-206 (2 figs.). 

 § Ann. Sci. Nat. (Zool.) xvii. (1913) pp. 207-18 (2 figs.). 

 il Rev. Suisse Zool., xxi. (1913) pp. 147-78 (1 pL). 

 t Zool. Jahrb., xxxiv. (1913) pp. 117-86 k.1 pi. and 40 figs.). 



