No. 390.] REVIEWS OF RECENT LITERATURE. 531 
but to several; and it seems as if they represent connecting links 
between these forms like ancestral types. There seem to exist, in 
the Tanganyika, numerous unknown species, chiefly in greater depths, 
but the author had no facilities to make a collection of the fauna of 
these depths. 
The halolimnic fauna of the Tanganyika, as a whole, has a striking 
Jurassic character. This fauna is positively wanting in the Lakes 
Nyassa, Meru, and Bangweolo, and — according to Gregory’s collec- 
tions — in the Lakes Naiwasha, Elineteita, Baringo, and — according 
to Donaldson Smith’s and Cavendish’s collections — in Lake Rudolf. 
Moore is of the opinion that the former connection of the Tangan- 
yika with the sea was in a northerly direction, through the Central 
African depression that is marked by the Lakes Albert and Albert- 
Edward to the Red Sea. Accordingly, we are to look for the same 
ancient fauna in these latter lakes, although their fauna is at present 
unknown. 
It may be that this body of sea water in Central Africa con- 
tinued to exist into Tertiary times, since we have some evidence — 
as the author points out — of the presence of marine Tertiary depos- 
its west of the Victoria lake, which seem to extend southward to the 
neighborhood of the Lake Nyassa. A.E. O. 
Swiss Rotifers.'— The appearance of the second part completes 
Dr. Weber’s superbly illustrated monograph of the Rotifera of the 
Léman. This paper is by far the most complete account of this 
group’ which has appeared since the publication of Hudson and 
Gosse’s Manual. In all, 127 species are described and figured with 
care. With commendable moderation Dr. Weber has refrained from 
describing any new species, but has devoted his attention to elaborate 
descriptions of the forms he has found and to an elucidation of their 
synonymy. ‘The result is a courageous reduction in the number of 
species, as is attested by the fact that no less than 292 names appear 
as synonyms in the index which concludes the final paper. The 
genus Brachionus has been a fruitful field for the species maker, 
and it is here that our author has done most execution. This 
genus includes many extremely variable forms, and the question of 
specific limits here is a most difficult one to solve. It may be that 
the statistical study of the group will throw some light upon the prob- 
lem.. The desirability of some designation for the many variants is 
1 Weber, E. F. Faune rotatorienne du bassin du Léman, 2me partie. Ploima 
et Scirtopoda. Rev. Suisse de Zool, T. v, pp. 355-785, Pls. 16-25, 1898. 
