XXVlll PROCEEDINGS OF THE 



The remarkable researches by which some considerable insight 

 has already been gained into the life-history of those mysterious 

 creatures, the parasitic worms, are still being carried on by 

 numerous observers with the happiest results ; and although there 

 is still much that is problematical in the history of some of the 

 commonest forms, investigators are now pretty well aware of the 

 direction in which their researches should be pushed. Professor 

 Leuckart, to whom we are indebted for much of the knowledge 

 which we already possess on this obscure department of zoology, 

 has lately published an important work on the parasites of 

 Man, and Dr. Cobbold a general Introduction to the Study of 

 Helminthology, both of which contain a great amount of valuable 

 zoological information. Professor Leuckart has also published 

 some " Helminthologische Mittheilungen," devoted almost entirely 

 to the description of the various modes of development prevailing 

 among the Nematode worms, and containing many highly inter- 

 esting original observations. 



Some valuable observations by Dr. Alexander Agassiz on the 

 embryology of the Echinodermata are given in the Memoirs of 

 the American Academy ; and Professor Baur publishes his three 

 memoirs on the natural history of Synapta digitata, in the first two 

 of which the anatomy and development of that singular creature are 

 described in considerable detail, while the third is devoted to the 

 investigation of the still more singular molluscan parasite which 

 was discovered in it by the late Johannes Miiller. 



In connexion with the Coelenterata, we shall call your attention 

 only to the first part of the 'Beitrage zur Naturgeschichte der 

 Hydromedusen,' lately published by Dr. Hackel, which contains 

 an account of a very singular mode of reproduction in some of the 

 Geryonidse. And of the literature treating of the lowest of all 

 forms of animal existence, we need only mention the first volume 

 of Dr. Bowerbank's ' Monograph of the British Spongiadse,' lately 

 published by the Eay Society, which contains an account of the 

 anatomical structure, physiology, and classification of Sponges in 

 general, with a discussion of the characters by which the species 

 may be distinguished. 



In systematic phsenogamous Botany I have not much to report 

 upon. But little progress has been made in the general works in 

 course of preparation, and the monographs published have been 

 but of little extent ; yet something has been done. Dr. Hooker 

 and myself have to apologize for the tardy issue of the second 



