1 58 Miscellaneous. 



portance in the lower animals, either from the intimate relations in 

 which it stands to the organs, or because of the liquid which it con- 

 tains. 



In the Hydra, the general cavity is entirely confounded with the 

 digestive cavity, for it contains no organs and replaces them all ; in 

 the Actinia it is prolonged into the tentacles, and in the middle of it 

 are suspended the reproductive organs and the alimentary canal, with 

 the latter of which it is in direct communication. 



In the Mollusca and Articulata, the general cavity is more circum- 

 scribed, and communicates directly with the circulatory system. 

 Lastly, in the Echinodermata and Annelida it is completely closed. 



Very apparent in some cases, in many others it is frequently dis- 

 guised by a network cf filaments, more or less close, which, uniting 

 the organs to the walls of the body, play the part of cellular tissue. 

 Between these two extremes every possible intermediate form is 

 found. 



Whatever may be the arrangement of the general cavity, it is always 

 lined with a membrane, which is produced with the various organs 

 communicating with it, and may be assimilated to a true peritoneum. 



The general cavity is always filled with a liquid, the nature of which 

 varies with the form of the cavity itself: if this communicates with 

 the digestive cavity, the liquid will be water, as may be seen in the Ac- 

 tinia ; if it communicates with the circulatory system, it will be full 

 of blood, which is the case in Insects, Crustacea, &c. Lastly, if it 

 be closed, it is filled with a serous fluid secreted by the membrane. 

 The functions of this liquid are important, for it takes a principal 

 part in nutrition, after having been submitted in various modes to 

 oxygenation ; it is in it that the eggs and spermatozoa are developed 

 and accomplish their different phases of evolution ; and lastly, it 

 assists in locomotion by causing exsertion of the locomotive organs 

 under the influence of muscular contraction. — Bill. Univ. de Geneve, 

 Sept. 1851, p. 72. 



EARLY FLOWERS. 



In a letter received from our friend Dr. T. Forster, dated Bruges, 

 Jan. 27, 1852, we are informed "that all the Tulipa suaveolentes 

 have flowered this year in January, while the Hyacinths and Narcissi 

 are a month behind time." 



Dr. Grant, F.R.S. 



A subscription is forming under the auspices of an influential com- 

 mittee of scientific men, chiefly naturalists, for the purpose of pre- 

 senting a testimonial to Dr. Grant, the eminent Professor of Compa- 

 rative Anatomy and Zoology in University College. Professor Grant 

 early relinquished the pecuniary advantages of his profession as a 

 physician, in order to devote himself unreservedly to the pursuits of 

 Comparative Anatomy and Zoology. He spent a considerable 



