Bibliographical Notices. 227 



tke contractile vesicle. If effective informing^ it could not bj 

 anj stretch of the imagination be truly regarded as the efficient 

 cause in the almost instantaneous reflux into the mass of the 

 bodj-substance of the ectosarc constituting the contractile 

 vesicle. Besides, according to Dr. Gruber, the pressure he 

 refers to is exercised at the jjosterior aspect of the Amoeba^ 

 and since the contractile vesicle almost always discharges 

 itself in that region, it would be doing so in the teeth of the 

 very force which is, at the very same time, exerting itself in 

 projecting pseudopodia in the opposite direction to the con- 

 tractile vesicle. 



Having for the present brought these observations to a 

 close, it only remains for me to assure Dr. Gruber that I am 

 extremely glad to find that so able a writer and thinker has 

 been led, although by a different route, to conclusions concern- 

 ing the relations between endosarc and ectosarc, and the pheno- 

 menon of pseudocyclosis, similar to those arrived at by me so 

 many years previously. 



BIBLIOGRAPHICAL NOTICES. 



Australian Museum. Catalogue of the Australian Hydroid 

 Zooiohytes. By W. M. Bale. Sydney : 1884r. 



The publication of the ' Catalogue of the Australian Hydroid 

 Zoophytes,' printed by order of the Trustees of the Australian 

 Museum, has supplied a want which has long been felt of a detailed 

 and critical account of the various species of Hydroids which have 

 been described from the Australian seas. Many of the older 

 species are known only by very brief descriptions, which, however 

 admirable at the time at which they were framed, have been 

 rendered, more especially in the absence of illustrative figures, 

 altogether indefinite, owing to the numerous allied forms which have 

 since come to light. 



The present Catalogue contains, besides the description of a large 

 mimber of new or lately known forms, redescriptions or amended 

 descriptions of many of these older species in those eases where their 

 identification has been possible, while supplementary characters and 

 original remarks, often with considerable detail, on many of the 

 genera and species which are described give additional value to the. 

 work. 



A special feature of the Catalogue is the large number of figures 

 which are given, and which, with but few exceptions, are from 

 original drawings. 



It will thus be seen that the work is a valuable contribution to 

 the literature on zoophytology, and will form an important landmark 

 in the history of the Australian zoophytes. 



