22 THE ROTIFERA. 



attention to the right use of the terms "dorsal " and "ventral " as applied to the Rotifera; 

 to the existence, in many species, of three antennae, holding definite positions with 

 respect to the dorsal and ventral surfaces ; to the true nature of the entrance to the 

 crop of Floscularia ; and to the structure and function of the vibratile tags. 



Dr. W. SALENSKY's paper, " Beitrage zur Entwicklungsgeschichte der Brachioims 

 urceolaris," ' traces the gradual changes in the ovum, from its first division into two 

 unequal spheres, through its complete segmentation, to the formation of the germinal 

 layers, and the evolution of the various organs of the completed embryo. Although 

 the paper deals with only a single species, it is our principal contribution to the Em- 

 bryology of the Rotifera. 



Dr. S. BARTSCH, in "Rotatoria Hungarian," 1877, and Herr KARL ECKSTEIN, 

 in " Die Rotatorien der Umgegend von Giessen," 2 have published treatises containing 

 descriptions and figures of local Rotifera (forty in Hungary and fifty at Giessen), in- 

 cluding two or three new species ; as well as new classifications of the whole class 



BOTIFEEA. 



Of Dr. BARTSCH's work I can say but little, as it is written unfortunately in Hun- 

 garian. His figures, though somewhat archaic, are well worth the studying ; and he gives 

 drawings and descriptions (happily this time in Latin) of six new species, of which two 

 had been recorded in England some years before. 



Herr ECKSTEIN also gives many interesting details of his local species, of which 

 two are new ; and adds a general discussion of the structure, development, affinities, and 

 classification of the whole class. His treatise also contains useful lists of synonyms, 

 as well as a good bibliography of the subject. 



The last edition (18G1) of PRITCHARD's " History of Infusoria," by Dr. Arlidge and 

 others, is a work differing in character from any of the above. About one-sixth of it is 

 devoted to the Rotifera, and contains descriptions of the whole of the then known species, 

 illustrated by a great many figures. Both the descriptions and the figures have been mainly 

 taken from Ehrenberg's work, which is closely followed throughout; but they have been 

 supplemented by others taken from the various treatises mentioned above. 



As a compilation, it is not only the best, but almost the only, English work on the 

 subject. It contains, moreover, an admirable and exhaustive treatise on " The General 

 History of the Rotifera " as a class, dealing minutely with their structure, reproduction, 

 development, systematic position, and classification. 



This original and most valuable essay may be said to be indispensable to all students 

 of the Rotifera, bringing together, as it does, into one point of view, the opinions of all 

 the best observers, on the many vexed questions that these little creatures have given 

 rise to, not only as to their organization and development, but as to their relations to 

 the rest of the animal kingdom. 



A full list of works on the Rotifera, including numerous papers that have been 

 published in various scientific periodicals, will be found at the end of this work. 



1 Sieb. u. Roll. Zcits. 1872. - Sieb. u. Roll. Zclts. 1883. 



