on the Organic Cojnposition of Chalk and Chalk Marl. 297 



visited the Red Sea during a period of eighteen months, name- 

 1}', nine months from tlie year 1823 to 1824, and an equal 

 number in 1825, having been nearly twelve months of the time 

 on board ship, in which interval they passed over nearly the 

 whole extent of that sea, saw many of its islands and coral 

 banks, and landed with a view to special examination on forty- 

 eight different points of the two coasts ; but the whole number 

 of islands and special points of the coast seen by them amounts 

 to about 150, independently of the long coast of Sinai in Ara- 

 bia, which they examined in continuity. In these laborious 

 efforts, attended with extreme danger, they collected 110 spe- 

 cies of Coral animals, being nearly three times as many as had 

 been found or described by all former observers, namely, by 

 Shaw, Forskal and Savigny, and later by Riippel. 



To determine the subjects of that collection with the greater 

 precision, it became necessary to undertake a review of the 

 M'hole class of the Coral animals, and the more so as Dr. 

 Ehrenberg found that his own observations were frequently 

 in collision with the systematic distinctions that have prevailed 

 up to the present time. In this review the author has espe- 

 cially compared the four most recent extensive systems, name- 

 ly, of Schweigger in 1820, Rapp in 1829, Cuvier in 1830, and 

 Blainville likewise in 1830, which may be said to embody the 

 judgment of the present generation upon the labours of earlier 

 periods, and to comprise the sum of existing knowledge in 

 this department of natural history. He has in particular 

 turned his attention to the work ot Blainville *, since it con- 

 tains the greatest number of new details, having been enriched 

 by the latest manuscript observations and drawings of Quoy 

 and Gaimard, the result of their second voyage round the 

 world with Capt. D'Urville. In these newer works, the la- 

 bours of Lamarck having been critically employed, the author 

 was relieved from the necessity of noticing them in a special 

 manner. 



The attempt to reconcile the observed discrepancies led the 

 author to separate the Coral animals into two organic natural 

 groups, which are well marked and distinct from each other, 

 and which he named Anthozoa (Flower-animals) and Bryozoa 

 (Moss-animals). In the course of these researches the author 

 found that the whole group of the Anthozoa, which consist of 

 the proper (single-mouthed) coral animals, and which had 

 been gradually distributed under more than 158 generic names, 

 including even heterogeneous animals and plants, might, ac- 

 cording to his own observations of their correspondence in 



* Dictionnairc des Sciences Naturclles, 1830, 



