57 



at Stat. 227, Lat. 4°5o'.5S. and Long. I27°59'E. Depth 2081 m. Bottom : grey mud with 

 an upper layer of brown, both mixed with sand, two species of Scalpellum 

 were taken, viz. Sc. ciliatum and formosutn. 



at Stat. 241, Lat. 4 24'. 3 S. and Long. i29°4c/.3 E. Depth 1570 m. Bottom: dark sand with 

 small stones, two species of Scalpellum were taken, viz. Sc. formosum and 

 sessüe. 

 and at Stat. 295, Lat. io°35'.6S. and Long. i24°u'.7E. Depth 2050111. Bottom: fine grey mud, 

 3 cm. thick, upper layer softer, brown with black stripes, two species of 

 Scalpellum were taken, viz. Sc. arcuatum and virgatum. 



Thus H. M.S. "Siboga" which made collections at 323 Stations in the Malay Archipelago 



met with species of the genus Scalpellum at 32 of these, and, while only one species was taken 



at 20 of these Stations, 



at 2 Stations the number of species found was 4, 



at 4 Stations the number of species found was 3, 



and at 6 Stations the number of species found was 2. 



Naturally, this may be considered as purely accidental ; one feels inclined to admit, 

 however, that certain places are especially favourable to the life or growth of Sca Ipellu ;;/-species. 

 That accident plays a great part cannot be denied; most of the species seem to be "rare" 

 animals and are represented by one or very few specimens only. 



Adding the 32 new species collected by the Siboga to the 93 of Gruvel's list of 1904 

 the number of species of the genus Scalpelhim would now be 125. In his Monograph Gruvel 

 has given extensive tables for the determination of the known species and I hardly think it ot 

 any use to give such tables again here. I think it will be possible to recognise the new species 

 with the aid of the description and the figure ; I point out for each species as a rule what 

 other species I consider its nearest relation and in what regards the two differ. 



Before entering on the description of the different species, a few remarks on the 

 classification of the genus may be permitted. The classification I have given in my Report on 

 the "Challenger"-Cirripedia, which afterwards was used and extended by Gruvel, though useful 

 for the determination of the species, cannot be said to be a good, that is a natural classification. 

 Such a system should give us, as far as possible at least, a representation of the descent or 

 origin of the different species. 



In 1883 I separated in the first place those species in which the valves were imperfectly 

 calcified. No doubt the importance of this character has been overestimated by me; I think 

 now it is of no great use, as there are species with perfectly calcified valves which in other 

 regards quite resemble those with imperfectly calcified valves; forms even occur with perfectly 

 and imperfectly calcified valves, which for the rest are so much alike, that they must be 

 considered as belonging to the same species. This is the case with Sc. Siearnsi Pilsbry and 

 with Sc. polymorpluim n. sp. 



The first question to be answered is which forms are the oldest, the earliest of the 

 now living species, and I think there can be no doubt that they are those species which, like 



57 



SIBOGA-EXPEDITIE XXXI <7. 8 



