488 



AULACODISCUS. 



A large number of the Aulacodiscus are found in fossil deposits, others 

 inhabit tropical seas, where they are sometimes found in immense numbers ; it 

 was in this way that my friend, Mr. Hens, in his Botanical expedition to the 

 Congo, found the sea coasts at Banana covered with a greenish bed of A. 

 Africanus Cott. (A. Kittoni Arnott var.), and was able at once to fill a large 

 vessel with this species, absolutely pure. 



The first general aspect 

 oiA . zonulatusRattr. is quite 

 different from an ordinary 

 Aulacodiscus, while Dr. 

 Pantocsek has made a 

 special genus of it under 

 the name of Tchestnovia 



( 



g. 224). 



Mr. A. Rattray has 

 published a good mono- 

 graph of this genus under 

 the title of " A revision of 

 the genus Aulacodiscus 

 Ehr." It will be found in 

 the Journal of the Royal 

 Microscopical Society for 



Fig. 224. Aulacodiscus zonulatus. 



the year tSSS. It is necessary to refer to it in studying this genus 



