262 



THE VOYAGE OF H.M.S. CHALLENGER. 



The preceding table shows — first, that the Challenger expedition obtained Simple 

 Ascidians in all of the seven great areas into which the seas of the globe have been 

 divided ; and secondly, that they were much more abundant in the Southern Pacific 

 Ocean 1 than in any of the other regions. 



Of the Molgulidse, Ascopera and Eugyra are confined to the Southern Ocean, while 

 Molgula is found in the Southern Ocean and also in the South Pacific, and round the 

 southern end of South America. Hence the family is not represented 2 in the Atlantic 

 Ocean, the North Pacific, and the Seas of the Malay Archipelago. 



The great family Cynthiidas has representatives in all the oceanic areas — and the 

 Bolteninse also occupy them all, with the exception of the South Atlantic and the Seas of 

 the Malay Archipelago. 



The Cynthinse are chiefly from the South Pacific area, but are also represented in the 

 North Pacific, the South Atlantic, and the Malay regions, while they are entirely absent 

 in the North Atlantic, the Southern Ocean, and round the southern end of America. 



The fctyelinse are also chiefly from the South Pacific Ocean, but are represented in all 

 the other areas, with the exception of the North Atlantic. 



The Ascidiidas arc entirely wanting only from the Seas of the Malay Archipelago, and 

 they are pretty equally distributed over the other six regions. 



The Clavelinidse, finally, occur in the North Atlantic, the South Atlantic, and the 

 Malay region, and are unrepresented in the remaining four areas. 



In the following table, the last illustrating the geographical distribution of the Ascidias 

 Simplices, the occurrence of the different genera and species according to the latitude is 



1 This region is of much greater extent than the " Southern Pacific Area " used previously (page 257), and 

 includes, in addition to it, the Australian region, in which a large number of species were obtained. 

 - All these statements as to distribution refer, of course, to the Challenger collection only. 



