267 



C ir rus of 5 th pair has unequal rami of 16 and 20 segments. The middle segments 

 bear three pairs of spines on the inner face : a pair of very small ones disposed about the 

 middle of the anterior margin, a pair of long ones near the extremity, and a pair of small 

 ones half way between both pairs. Hairs on outer face near extremity of segments rather long. 



Cirrus of 6 lh pair (PI. XXVII, fig. 16). Rami not very unequal, of 20 and 22 seg- 

 ments. Greatest number of spines on the inner face of the middle segments 3 pairs — as 

 on the segments of the 5 th cirrus. Spine-like hairs disposed at the extremity of the segments 

 on outer face nearly as long as the segments themselves. 



Penis long, growing narrower towards the extremity. Very few hairs only are seen 

 scattered over surface, hardly any hairs at the extremity. 



The only specimen of this species that the Siboga collected was dredged at : 



Stat. 313. February 14/16, 1900. Anchorage East of Dangar Besar, Saleh- (or Sapeh-)bay. 

 Depth up to 36 m. Bottom : sand, coral, and mud. 



Genus Chthamalus Ranzani 



Darwin described eight species of Chthamalus in his Monograph (1854). The "Chal- 

 lenger" collected a Cirripede belonging to this genus which I introduced into science as a 

 ninth species. So far as I know, no other forms or species of this genus have been col- 

 lected, nor has our knowledge of the habits, distribution etc. of the known species greatly 

 increased since Darwin published his Monograph. 



Only two of these species have been observed in the Malay Archipelago {Ch. stellatus 

 Poli and Ch. intertextus Darwin); two other forms, however, were collected in "adjacent" 

 waters : Ch. antennatus Darwin at New South Wales and van Diemensland and Ch. challengeri 

 Hoek taken from the screw of the frigate, after having remained for some time in the waters 

 of Japan. (Gruvel 1 says that Ch. antennatus occurs also in Chili, but he does not mention 

 the author who observed it there.) 



Ch. stellatus is the only species that is widely distributed : it lives on the coast-rocks 

 of Southern Europe, of the Southern United States, also at Woodshole (Sumner), on the 

 coasts of Brazil, of the Red Sea, coast of Bengal, the Philippine Archipelago, coast of China, of 

 California etc. So far as our knowledge goes, all the other species — with the exception of 

 the somewhat problematic case of Ch. antennatus mentioned above — have only a much 

 more limited or even local distribution. Yet Ch. stellatus was not observed attached to noating 

 objects, as was the case with Ch. dentatus and Ch. challengeri which were taken from ships' 

 bottoms. Like most of the other species, Ch. stellatus lives attached to littoral rocks, none of 

 the species having been observed at any important depth. 



H. M. S. "Siboga" brought home specimens of two species belonging to this genus. 



1. Chthamalus stellatus Poli. PI. XXVII, fig. 17—22. 



Darwin, Ch., Monograph. The Balanidae, Verrucidae etc. 1854. p. 455, pi. XVIII, fig. la—ih. 



1 Gruvei , A., Monographie des Cirrhipèdes. 1905. p. 203. 



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