third natural group : the first with small, the second with rudimentary, the third without terga. 

 For the sake of convenience, such a classification may be used; but studying a few of the 

 species more carefully one soon discovers, that the affinities between the different species cannot 

 be made out by the shape or size or the greater or less development of parts of the capitulum 

 only. To show how complicated the relations are I need only refer to the new species P. 

 obliquum found by the "Siboga" and to be described later. With its miniature terga it seems 

 very naturally to bridge over the gap between P . crassum with small and P. cbtirncum without 

 terga; yet the arrangement of the spines on the cirri in P. obliq7iti>ii is quite different from 

 what it is in P. ebjtrneuvi and shows that it is perfectly impossible to consider them as nearly 

 related. In this regard P . obliqjttan seems to be nearly allied to P. fissum -, in the presence, 

 however, of a distinct line running from the umbo to the upper end of the scutum P. eburneum 

 approaches to P. Jissuni much more than P . obliqiiiun does. 



The geographical distribution of the species of Poecilasnia is only imperfectl)- known as 

 yet. Two species have been observed in the Atlantic and also in the Pacific; a very large 

 pro])ortion of the known species inhabit the Malay Archipelago, as may be seen from the 

 followingf list : 



t> 



Poecilasma Kaempferi Darwin (with P. auraiitiuin Darwin), Japan, Madeira, 350 a 400 m. 



(Gruvel), Gulf of Manaar, 775 m. (Annandale). 

 Poecilas7na dubium n. sp., Malay Archipelago, 204 to 304 m. 



Poecilasma carinatufn Hoek, West Indies, Atlantic, Malay Archipelago, 600 to 1633 m. 

 Poecilasma gracile Hoek, Australia, Malay Archipelago, 521 — 750 m. 

 PoecilasiJia fissiim Darwin (with P . amygdabiin Auriv. and P. lenticula Auriv.), Malay Archipelago, 



Philippines, Australia (Weltner ^), Andamans (Annandale "). Low water. 

 Poecilasma excavahim n. sp., Malay Archipelago, 289 — 304 m. 

 Poecilasma mimctuiii Gruvel ? 

 Poecilasma tridens Auriv., Philippines. Depth? 

 Poecilasma vagans Auriv., probably East India. Pelagic? 



Poecilasma crassitm J. E. Gray, Madeira (Darwin), Azores (Gruvel). Depth? 

 Poecilasma iinguicuhis Auriv., Azores, 880 m. 

 Poecilasma obliqtmm n. sp., Malay xArchipelago, 204 — 304 m. 

 Poecilasma eburneum Hinds, Malay Archipelago, ? Red Sea (Weltner *), 40 — 90 m. 



Poecilasma Kaempfcri (with P. aiirantiuni) and P. carinatum are so far as at present 

 known the only species inhabiting both the Atlantic and the Indian C^cean. Gruvel * says that 

 P. crassum [from Madeira (Darwin)J and the Azores occurs also in the Philippine Archipelago, 

 Island of Bohol, but I suspect that this is an error; I do not know at any rate, on whose 

 authority this is stated. 



' Weltner, W., Cinipedien einer Reise D.ich dem Pacific. Zoolog. Jahrbiicher. Al)t. fiir Systematik, XIL 1S99. 



2 Annandale, N., Malaysian Bainacles in the Indian Museum. Memoirs of the .Asiatic Society of Bengal, I, 5i '905- 



•> Weltner, W., Verzeichnis der bishev beschiiebenen lecenten Cirripedienaiten. Archiv f. Natuigeschichte, 1897, Bd I, H. 3. 



■• Gruvel, A., Monographic des Cirrhipedes. Paris, 1905, p. 116. 



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