ASTROLABE 7 ^ to Road Island, Ambon (in the Moluccas), and 

 to the coast of the Vanikoro Islands (between the New Hebrides 

 and the Solomon Islands) . During this time they discovered 

 this small transparent tunicate, which they described and 

 presented only incompletely, and for which they suggested the 

 generic name Doliolwn. 



Later T. Huxley, on a tour around the world aboard the 

 ship RATTLESNAKE, saw doliola in the southern part of 

 the Pacific Ocean and described their structure more exactly 

 and in more detail than Quoy and Gaimard,77 but in his notes 

 the male genital glands were given for individuals of sexual 

 regeneration. 



Krohn, for the first time, discovered the presence of 

 doliola in the Mediterranean Sea (near Messina and Naples) , 

 studied the structure and described three new species. 

 According to Krohn, doliola "are free living ascidians, but 

 in many respects are similar to salpa and form, therefore, an 

 interesting intermediate link between both these orders of 

 tunicates" (p. 53). From Krohn's description, the structure and 

 reproduction of doliolum, according to the majority of the 

 features, must be related to salpa; this applies also in the 

 present taxonomy. 



Krohn observed that from the ova of doliola cercaria- 

 like larvae develop which later undergo metamorphosis . 

 The peculiarities of the larvae are connected, according 

 to Krohn, with the mode of life of the tunicates more than to 

 ascidians, which are in their adult condition fastened motion- 

 less to the substrate. In accordance with this, in the ascidian 

 larvae the tail disappears early, but in the larvae of doliola 

 it remains throughout metamorphosis and serves as an organ 

 of movement. The process of reduction of the tail in the larvae 



76. VOYAGE DE DECOUVERTE DE L' ASTROLABE EXECUTE PAR 

 ORDRE DU ROI PENDANT LES ANNEES 1826 - 29 SOUS 

 LE COMMANDEMENT DE M. J. DUMONT D'URVILLE. 

 ZOOLOGIE PAR MM QUOY ET GAIMARD, vol. 3 (1834). 



77. T. Huxley, "Remarks upon Appendicularia and Doliolum, 

 Two Genera of Tunicates," PHIL. TRANS. ROY. SOC . 

 LONDON (1851), pp. 599 - 602. 



587 



