tas 
267 
: ecw: Mee ; 
Cirrus of 5 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 pair (Pl. 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 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. zntertextus Darwin); two other forms, however, were collected in “adjacent” 
waters: Ch. antennatus Darwin at New South Wales and van Diemensland and Ch. challenger 
Hoek taken from the screw of the frigate, after having remained for some time in the waters 
of Japan. (GruvEL’ 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. ste//atus was not observed attached to floating 
objects, as was the case with Ch. dentatus and Ch. challengert which were taken from ships’ 
bottoms. Like most of the other species, Ch. ste//atus 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. Pl. XXVII, fig. 17—22. 
DARWIN, CH., Monograph. The Balanidae, Verrucidae etc. 1854. p. 455, pl. XVIII, fig. 1a—1/. 
1 GruveL, A., Monographie des Cirrhipédes. 1905. p. 203. 
139 
