444 SUMMARY OP CURRENT RESEARCHES RELATING TO 



becomes narrowed anteriorly to form the oviduct : the two oviducts 

 soon unite to form a short canal to the exterior. Opening into this 

 common canal is an accessory gland on each side, formed of numerous 

 unicellular glands imbedded in connective tissue. The author 

 regards the structure of the genital system as proving the affinity 

 between Pontohdella and Branchellion. 



Classification and Morphology of the Oligochseta.*— Prof. F. 

 Vejdovsky has published in a connected and handsome form an 

 account of the Oligochjeta. 



After a full bibliographical list, the author describes in order 

 the families, genera, and species. Ten families — Aphanoneura, 

 Naidomorpha, Chsetogastrid^, Discodrilidse, EnchytrsBidse, Tubi- 

 ficidse, Phreoryctidse, LumbriculidEe, Criodrilidee, and Lumbricidae — 

 are recognized. 



In the second part of the work, the dermomuscular tube with the 

 hypodermis and hypoderraal glands of the cilia; the phosphorescence 

 of earthworms ; the structure of the cuticle, and the arrangement of the 

 muscular layers, are discussed ; this is followed by an account of the 

 setae, coelom, mesenteries, and orifices of the body-cavity ; the chapter 

 on the nervous system not only gives an account of the topography 

 and external form of the central nervous system, but describes the 

 peripheral system, the histology of the fibres and cells, and the lateral 

 cords of ganglionic cells and the visceral nervous system. Then 

 follows an account of the ciliated pits and of the various organs of 

 sense. The digestive, vascular, and excretory organs are fully described 

 and great attention is given to a history of the generative apparatus, 

 its degeneration and its morphology, and to the process of fission as 

 seen in Molosoma tenebrarum. 



The author fails to recognize the necessity of making any group 

 of " Archiannelides," for the moment we distinguish Oligochaeta from 

 Polych^ta we find that the archiannelid ^olosoma belongs to the 

 former, and Ctenodrilus, Parthenope, Monostylos, Polygordius, &c., 

 belong to the latter group. This monograph is one which will be 

 consulted by every student of Annelids. 



Studies on Earthworms.! — Mr. W. B. Benham, after an historical 

 introduction and an account of previously described genera, gives a 

 table of the characters of the genera of earthworms, in which notice is 

 taken of the group (ante-, intra-, or post-clitelline) to which they 

 belong, of the somite at which the clitellum commences, of the number 

 of somites through which it extends, of the position of the male pore, of 

 the characters of the copulatory appendage, the position and number 

 of the spermathecoe, of the number of setaa per somite and of the mode 

 in which they are arranged, of the position of the nephridiopore, length, 

 and habitat; a list of all known earthworms whose distribution is known 

 is next given. In the third part the variations in the structure of earth- 

 worms treated according to the different systems of organs are described; 



* ' System u. Morphologie der Oligochjeten.' fol., Prag, 1884, 172 pp. 

 and 16 pis. 



t Quart. Journ. Micr. Sci., xxvi. (1886) pp. 213-301 (3 pis.). 



