153 



At Station 204: B. compressus n. sp., and B. proripiens n. sp. At this Station two 



species of Scalpellum also were collected (See p. 56 of this report). 

 At Station 260: B. aldus n. sp. B. auricoma n. sp., and B. investitus n. sp. 

 At Station 310: B. investitus n. sp., B. maculatus n. sp., and B. maldivensis. 



All the species of Balamts were found in the neighbourhood of the coast. Several of 

 them were caught in shallow water, some in rather deeper water, and only a few in water 

 of greater depth than 100 m. The greatest depth found inhabited by a species of this genus 

 was 564 m. ; at depths of more than 600 m., at which 26 species of Scalpellum were collected, 

 not a single species of Balamts was observed. 



Several species seem to spread over a rather considerable range of depth : as for 

 example B. maldivensis, which was observed at depths of 54 — 91 m., 70 m., 216 m., and 

 even of 390 m., and B. albus at depths of 90 m., 289 m., and, probably, even at a depth of 

 522 m. The following table contains the species of Balamts collected during the cruise of the 

 Siboga, arranged according to the depth at which they occurred : 



B. hystrix n. sp. . . 

 B. navicula Darwin . 

 B. terebratus Darwin 



40 m. (or less) 



45 m- 

 52 m. 



/ ó 



in. 



B. maldivensisV>oxr^2}\G. 54 — 390 m. 



B. maculatus n. sp. ... 70 — 



B. investitus n. sp. . 



B. proripiens n. sp. 



B. compressus n. sp. 



B. minutus n. sp. . . 



B. albus n. sp. . . . 



B. pentacrini n. sp. . 



B. tennis Hoek . . . 



73— 90 m. 



75—94 m. 



75 — 1 1 2 m. 



80 m. 



90 — 289 (and? 522 m.) 



204—304 m. 



275 m. 



B alatus n. sp 564 m. 



A few remarks may be added with regard to the geographical distribution of these species 

 of Balanus. That 16 species were collected, which were not observed before, does not prove, 

 of course, that they do not occur outside the Malay Archipelago : the exploration of this region 

 on this occasion has been a very careful one ; therefore, it cannot be considered improbable, 

 that at least some of these species will be found in other regions of Eastern Asia, should 

 they be explored with the same care and thoroughness, as the Malay Archipelago has been. 

 Of the species collected by H. M. S. "Siboga", which were already known, B. amphitrite and 

 B. tintinnabulum seem to have the widest distribution, which no doubt is due partly to their 

 being often found on ships-bottoms: they are sometimes associated with one another even on the 

 same ship. B. calceolus, B. navicttla, B. amaryllis, and B. maldivensis are known to occur in 

 British India also, and B. amaryllis in Australia as well. B. quadrivittatus, B. socialis, and B. 



SIBOGA-EXPEDITIE XXXI b. 



