ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 155 



it differ in outline in different localities, but in the same locality at 

 different seasons. From probably being polycyclic, it has become mono- 

 cyclic in Lake Constance, and practically acyclic in Lake Mendota and 

 the Lukes of Holstein. In Britain it is most likely monocyclic, but has 

 not been sufficiently studied. 



Marine Crustacea in a German Lake.* — Dr. M. Samter and Dr. 

 W. Weltner record Mysis relicta, Pallasiella quadrispinosa, and Ponto- 

 poreia qftinis in the Madii Lake on the Baltic coast of Pomerauia 

 The occurrence of these three species in inland lakes in Sweden, 

 Norway, Finland, &c, has been generally accepted as indicating that 

 such lakes were formerly connected with the sea, and are relics of a great 

 ocean. Their presence in the Madii Lake makes the hypothesis difficult 

 of acceptance in this case, as My sis relicta appears to be derived from 

 M. oculata, and this species does not occur in the Baltic. After a very 

 elaborate discussion of the matter from the geological standpoint, the 

 authors conclude that the Madii is a remnant of a great fresh-water 

 basin which communicated with the North Sea at a time when this, 

 owing to melting ice, was largely brackish. In this North Sea there 

 must havo lived a fauna whose members could tolerate considerable 

 variations in the density of the water. From this fauna has arisen the 

 "marine" element in the fauna of the Madii by a gradual process of 

 adaptation, as the volume of fresh water poured into the North Sea 

 diminished in amount. 



Position of the Scinidse.t — Prof. J. Vosseler discusses the position 

 of this family of Amphipods, which has hitherto contained only one 

 genus. He rapidly surveys the structure of the Amphipoda in general, 

 with a view to ascertaining the classificatory value of the various organs. 

 His survey leads him to the conclusion that the Scinidae cannot be sepa- 

 rated from the Hyperiidae as Chun and Garbowski suggest, but must be 

 regarded as true Hyperiidae, probably closely related to the Xipho- 

 cephalidas. He further describes as Acantlioscina serrata g. et sp. n., a 

 new type of the family in which the first two thoracic segments are 

 fused, a character hitherto known only in some Hyperiidae. 



Subterranean Amphipoda of Britain. J — Dr. Charles Chilton gives- 

 full details of the four known British species, with a revision of the 

 nomenclature and notes on distribution. He notes that as yet no sub- 

 terranean Amphipod has been found in Scotland. 



Annulata. 



Origin of Segmented Worms. § — Dr. H. M. Bernard suggests that the 

 origin of segmented worms may be looked for in free-swimming Ccelen- 

 tera " trailing behind them longer or shorter strings of buds diminishing 

 in size progressively backwards." The posterior buds would tend to 

 be poorly nourished ; apertures can occur almost anywhere in the 

 Ccelenterate wall ; a posterior opening might early be developed in 

 order to free the terminal buds from their useless and deleterious 



• Zool. Anzeig., xxiii. (1900) pp. 638-54. 



i Tom. cit., pp. 662-76 (4 figs.)- 



X Journ. Linn. Soc. (Zool.), xxviii. (1900) pp. 140-60 (3 pis.). 



§ Ann. Nat. Hist., vi. (1900) pp. 509-20. 



