408 TRANSACTIONS OP SECTION D. 



species, and (I am almost sorry to say) nineteen of these must be considered 

 as new to science. Most of these were dredged at some depth, the already 

 known and described species of the collection being to a large extent (as is easily 

 understood) those collected during shore exploration. Few species, however, 

 were brought up from great depths ; most of them inhabit water the depth of 

 which does not exceed 75 to 90 m. At very considerable depth no species of 

 Balanus was collected, those brought up from the deepest water being : — 



B. alatus, n.sp. . . from 564 m. B. pentacrini, n.sp. . from 304 m. 

 B. albus, n.sp. . . ,, 289m. IB. tenuis (Hoek) . . ,, 275m. 

 B. echinicola, n.sp. . ,, 216m. t B. velutinus, n.sp. . ,, 390 m. 



Of the first three of these species, however, specimens were also collected at 

 a depth of less than 100 m. 



In the rich and interesting collections brought home by the ' Challenger,' the 

 Cirripedia of which I had the pleasure to work up, the genus Balanus was 

 found represented by nine species, two of which belonged to a special section 

 of deep-sea forms. Since the publication of my report (1883) two species more 

 of this section were described by Pilsbry. The new ' Siboga ' species, B. velu- 

 tinus, belongs also to this section, so that we know five species at present, the 

 distribution of which is a very wide one, as may be judged from the following : — 



B. corolliformis (Hoek), 270 m., between Kerguelen and Heard 



Islands ; 

 B. hirsutus (Hoek), 930 m., Faroe Channel; 

 B. hoekianus (Pilsbry), 77 m., Bering Sea; 

 B. rallisto derma (Pilsbry), 140 m., Suruga Gulf, Japan; and 

 B. velutinus, n.sp., 204-390 m., Malay Archipelago. 



The species of this section are characterised by the compartments want- 

 ing radii and (so far I have investigated the species myself) by the struc- 

 ture of the labrum, which has no notch and no teeth or a row of numerous 

 little nobs instead of such teeth. I think, however, we do better not to con- 

 sider these forms as more primitive than those with radii and teeth on both 

 sides of a notched labrum, but rather as species somewhat degenerated perhaps 

 in consequence of isolation. 



Of the remaining new species three belong to Darwin's section B, species 

 with boat-shaped basis attached to Gorgonire, Millepora?, &c, and one to sec- 

 tion E, which species is nearly related to Darwin's B. declivis. The remaining, 

 fourteen in all, forming a large proportion of the new species, belong to Dar- 

 win's section F, the species of which have the parietes and radii not permeated 

 by pores, and the basis sometimes permeated and sometimes not permeated by 

 pores and sometimes extremely thin. These species caused me great trouble. 

 A very detailed study of the compartments, of the opercular valves, and of the 

 animal's body was necessary to determine them, the difficulty being greatly 

 enlarged by the circumstance that the dredged species as a rule are represented 

 by single or very few specimens only. For the description of the new species, 

 most of which are interesting in several respects, the printed report is to be 

 consulted, which will be put in the press at an early date. 



The species of Balanus observed in the Malay Archipelago, with few excep- 

 tions only — B. amphitrite, B. amaryllis, B. tintinnabuhnn, &c. — seem to have 

 a limited geographical distribution ; at least as far as we know at present. For 

 we are not to forget that the marine fauna of some parts of the world's surface 

 has not up till now been so carefully investigated as is the case with the Malay 

 Archipelago. Moreover, a very detailed description of a species of Balanus is 

 necessary to recognise it with certainty. I think it is a most interesting genus 

 — but notwithstanding the most excellent way in which Darwin started its study, 

 it has, perhaps in consequence of the difficulties attached to it, been somewhat 

 neglected hitherto. Perhaps my investigation of the ' Siboga ' species will 

 encourage others to continue the study of these animals. They will not be dis- 

 appointed. 



