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 Perisporiaceae or " Moulds," and (3) the Saccharo- 

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

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

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

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

 takes place.'*' Although the next 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 

 Gallus 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. 



PROCEEDINGS 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 Pedinothuria 

 and Elikodiadema, two new Subgenera of Echinoidea/ By J. W. 

 Gregory, D.Sc., F.G.S. 



The Author summarizes and discusses the literature bearing upon 

 the Echinothuridae, and brings forward arguments to prove that the 

 family is a member of the order Diademoidea, arid is derived from 

 the Pedinid, members of which are found in earlier rocks than the 

 Corallian, which contains the oldest member of the Echinothuridae, 

 namely, Pelanechinus. He maintains that the extreme flexibility 

 and loose articulation of the plates of the living genera Asthenosoma 

 and Phormcsoma is due to the diminished calcification of the plates, 

 and that these recent genera are extremely specialized forms, and 

 not primitive, the apparently primitive features of the family being 

 secondarily acquired, not primaeval. 



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

 described as Pedinothuria a connecting-link between the PedinidaB 

 and Echinothuridae ; and Elikodiadema which has a flexible test, is 



