74 
W. MICHAELSEN : 
VOLUME II, Part 10.— COPELATA and THALIACEA. 
By Prof. H. Lohmann (Kiel). 
Pp. 143-149, with 1 figure in the text. 
With the exception of one species of Doliolum, the pelagic 
Tunicata belong to the class of Appendicularia. Salpae and 
Pyrosomcle were not found. Appendicularia were contained in 
nine hauls of the tow net, six from Sharks Bay and three from the 
Fremantle region. Most of these hauls showed the influence 
of the shallow coastal area, Oikopleura dioica predominating in 
them. But three hauls from Sharks Baj ? were exceptional, as 
they contained four other species of Oikopleura ( 0 . longicauda, 
0 . fusiformis , 0 . rufesc-ens, and 0 . cophocerca). All these species 
of Oikopleura belong to the warm-water fauna and are generally 
distributed over all three oceans ; but, whilst the latter species 
generally occur at a distance from the coast, and do not extend 
beyond the limits of warm water, 0 . dioica is, on the contrary, 
abundant on the coasts, and extends far into the region of cooler 
waters. 1 he three collections with open-water species were 
caught in the South Passage of Sharks Bay, where at flood-tide 
a strong current enters from the open sea. The influence of this 
current may be seen in the relative composition of the different 
hauls. On approaching the South Passage the number of species 
increases and, whilst the number of 0 . dioica diminishes, that of 
the open-water species increases, especially that of O. longicauda 
and 0 . fusiformis. O. cophocerca appears only immediately op- 
posite the South Passage. No species characteristic of the 
Westwind-drift " were found. Especially remarkable is the 
absence of Frilillaria borealis in the hauls from the Fremantle 
area. 
COPELATA. 
Oikopleura cophocerca. Gegenb. — Sharks Bay, between Inner Bar 
and South Passage. 
,, rufescens, Fol. -Sharks Bay, between Inner Bay and 
South Passage, and near Dirk Hartog I., off Brown 
Station. 
,, longicauda, Vogt. -Sharks Bay, at the same localities. 
,, fusiformis, Fol. -Sharks Bay, at the same localities. 
,, dioica, Fol. Sharks Bay, between Inner Bar and 
South Passage, and off Denham, Swan River off 
North Fremantle, Cockburn Sound. 
Frilillaria abjornseni , n. sp.- Fremantle, Cockburn Sound, Swan 
River off North Fremantle. 
THALIACEA. 
Dolhhni denticulatum , O. and G. — Sharks Bay, between Inner Bar 
and South Passage. 
