346 Bibliographical Notices. 



works that it has produced. Since its establishment in 1844, 

 British naturalists, and especialJy zoologists, have had to thank the 

 Ray Society for so many splendid monographs, that its activity 

 must be familiar to every one ; and we can only regret that an 

 organization which has effected so much should appear to be lan- 

 guishing for want of well-merited support. The last publication of 

 the Society, the title of which stands at the head of this notice, 

 fully maintains the high reputation which has been gained by former 

 productions, and will be welcome to many workers. 



Some thirty years ago, in the time of its early youth and vigour, 

 the Eay Society published a ' Natural History of the British Ento- 

 mostraca,' by the late Dr. William Baird, a work which embodied 

 all that was known at the time of the Entomostracan Crustacea 

 inhabiting these islands. At that date, however, comparatively 

 little attention had been paid to these denizens of our shores and 

 fresh waters ; and, indeed, the information given by Dr. Baird was, 

 to a very great extent, acctimulated by his own personal labours. 

 With his book as a guide the investigation of the Entomostraca 

 became a much easier matter than before, and the number of students 

 who paid some attention to them naturally increased. At the same 

 time dredging-operations were more systematically carried on ; and 

 new materials were thus constantly being brought to light, increas- 

 ing enormously the number of known forms which might fairly be 

 regarded as British. 



Moreover the zoologists of other countries have not been idle ; 

 and, in fact, they have done more in the way of describing new 

 generic and specific types than those of Britain ; so that the literature 

 of the Entomostraca has of late years been greatly increased, espe- 

 cially at the hands of Scandinavian naturalists. In the work now 

 under consideration Dr. Brady describes the British genera and 

 species of the order Copepoda as limited by Baird — that is to say, 

 the free and semi-parasitic forms, leaving out of consideration the 

 truly parasitic types regarded by many recent zoologists as 

 Copepods, with which, indeed, they are directly affiliated by their 

 developmental history. 



Some notion of the progress that has been made in the study of 

 these little creatures may be formed from a mere comparative state- 

 ment of numbers. Baird, writing thirty years ago, recognized only 

 13 species of Copepoda ; Dr. Brady in his present work describes 

 151. It is true that a certain proportion of this addition may be 

 due to the recognition of specific diversity where unity was formerly 

 supposed to prevail, as is strikingly shown in the case of the genus 

 Cyclops, in which, while Baird admits only the single species C. 

 qtiadnconiis, Dr. Brady describes 14 species ; but it must be 

 chiefly ascribed to the discovery of new forms, especially among the 

 inhabitants of the sea and brackish waters. 



In his treatment of his subject Dr. Brady adopts the division of the 

 Copepoda into three great sections, as proposed by Thorell , — namely: 

 Gnathostoma, with a pair of mandibles and three pairs of maxillae ; 

 Poecilostoma, with no mandibles, but with from one to three pairs 

 of maxillae ; and Siphonostoma, with a siphonate mouth usually 



