94 NATURAL SCIENCE. april. 



There are many advantages in comprehensive handbooks prepared 

 by a single author. They present a uniformity of plan and treatment 

 that is nearly always lacking in composite works. In these days of 

 specialisation, however, the production of such handbooks is becoming 

 almost impossible ; and most of the larger treatises are the result of 

 the labours of many compilers. According to the Zoologischey Anzeigey 

 of February i, another of these indispensable works of reference is 

 being prepared, and we may hope within the next few years to have 

 a great Manual of Zoology written by a number of the most eminent 

 specialists in Europe. The respective authors desire that they may 

 be promptly furnished with reprints of all new papers and memoirs 

 relating to their various subjects, as enumerated below : — 



Rhizopoda, Ciliata, and Suctoria — Dr. Fabre-Domerque, Paris. Sporozoa — 

 Professor Moniez, Lille. Flagellata — Professor Kiinstler, Bordeaux. Porifera — 

 Professor Vosmaer, Utrecht. Anthozoa — Professor Kiinstler. Hydrozoa, Siphono- 

 phora, Acephala, Ctenophora — Professor Lang, Zurich. Dicyemidae — Professor 

 Van Beneden, Liege. Orthonectidse — Professor Julin, Litge. Trematoda, Cestoda 

 — Professor Moniez. Turbellaria— Professor Lang. Rotifera, Gastrotricha — M. 

 De Guerne, Paris. Archi-annelida, Sternaspida, Phoronida — Professor Roule, 

 Toulouse. Hirudinea — Professor De Nabias, Bordeau.x. Annelida — Professor 

 Yung, Geneva. Bryozoa — Professor Cuenot, Nancy. Brachiopoda — Professor 

 Joubin, Rennes. Mollusca — Professor Pelseneer, Ghent. Protracheata — Professor 

 Vayssiere, Marseilles. Nemathelminthea, Acanthocephala — Professor Kohler, 

 Lyon. Nemertea, Chsetognatha — Professor Joubin. Linguatulida, Tardigrada, 

 Pycnogonida, Arachnida — Professor Barrois, Lille. Myriopoda, Insecta — Professor 

 Vayssiere. Crustacea — Professor Giard, Paris. Echinodermata — Professor 

 Cuenot. Enteropneusta — Professor Kohler. Tunicata — Professor Van Beneden. 

 Amphioxus, Cyclostomata — Professor Julin. Pisces, Amphibia, Reptilia, Aves — 

 M. L. Dollo, Brussels. Mammalia (except Primates) — Professor Weber, Amsterdam. 

 Primates, including Homo — Dr. Deniker, Paris. 



Some time ago we heard rumours of a similar Manual projected at 

 Cambridge, to be undertaken by British naturalists ; but there is as 

 yet no definite announcement. 



The supposed discovery of pseudopodia in diatoms, announced 

 by Mr. J. G. Grenfell in the Quavtevly Jonvnal of Micvoscopical 

 Science for October last, is still being disputed by experienced 

 observers. In the January number of the I nteynational Journal 

 of Microscopy and Natural Science, issued late last month, Mr. 

 Jabez Hogg adds his testimony to that of other critics, and briefly 

 disposes of the so-called evidence of " pseudopodia." Mr. Hogg con- 

 firms the view of Mr. G. H. Bryan that the processes in question 

 "are, in no sense of the word, pseudopodia, neither are they, nor can 

 they be, regarded as organs of locomotion ; and their discovery — 

 which, by the way, is a very aged one — throws no liglit whatever on 

 the debatable question : the movements of diatoms. These spinous 

 processes have been described over and over again. Their composi- 

 tion is simple enough: Organic matter, carbonate of lime, and a 

 slight admixture of a silicatcd peroxide. They are apparently 

 secreted by the diatom for the purpose of affording a rigid support to 



