238 Geological Society. 



Passing to the Vegetable Parasites, the author does not seem to 

 be so much at home as with the Animal. They are divided in 

 rather a curious "way, viz. : (1) the Dermatophytes, or cutaneous 

 parasites, (2) the Perisporiacca) or " Moulds," and (-S) the 8accharo- 

 mycetes. An Aspergillus is described as " formed of tliin colourless 

 tilaments forming a matted layer or thallus, and a looser mass above, 

 the so-called aerial mycelium." By the inoculation of the spores 

 of A. fymigatus it is stated that" tuberculosis of the liver and lungs 

 takes place,'' Although the nest sentence renders the author's 

 meaning clear, it is to be regretted that the term " tuberculosis," 

 which is now applied only to a specific disease, should be used in 

 an anatomical sense. The bacterial diseases are not described, as 

 the author considers that they should be separately dealt with. 

 Two appendices (one a complete list of the parasites attacking 

 Oiilhis domesticus, the other a bibliography) and a good index 

 complete the volume, which is illustrated with many capital wood- 

 cuts. 



In spite of the blemishes mentioned above, the work supplies a 

 distinct want and will prove a useful guide to the recognition and 

 treatment of the parasitic diseases of poultry. 



PllOCEEDINGS OF LEARNED SOCIETIES. 



GEOLOGICAL SOCIETY. 



December 2, 1896.— Dr. Henry Hicks, F.R.S., 

 President, in the Chair. 



The following communications were read : — 



1. 'On the Affinities of the Echinothurida', and on Pedlnothuria 

 and ElihnJiadtina, two new Subgenera of Echinoidea.' By J. \V. 

 Gregory, D.Sc. F.U.S. 



The Author summarizes and discusses the literature bearing upon 

 the Echinothurida', and brings forward arguments to prove that the 

 family is a member of the order Diadcmuidea, and is dciived from 

 the Pcdinida", members of which are found in earlier nx ks than the 

 Corallian, wiiich contains the oldest member of the Echinothuridae, 

 namely, J'tlonichinus. He maintains that the extreme flexibility 

 and loose articulation of the plates of the living genera AstJunosuma 

 and I'horwosonia is due to the diminished cakilication of tlie plates, 

 and that these recent genera are extremely specialized forms, and 

 not piimitive, — the ai)parcntly primitive features of the family being 

 secondarily acquired, not primieval. 



A description is given of forms belonging to two new genera, 

 described as Pedinolhurin — a connecting-link between the IVdinidae 

 .•\nd Echinothurida^ ; and Elikodiadenia — which has a flexible test, is 



