2 I 



1894 (/3) Topsent p. 8 — 9. 



1896 Topsent pp. 115, 125. 



1900 Topsent pp. 5, 10, 21, 107 — 110; PI. III, fig. 8. 



1909 Hentschel p. 385. 



I am sorry to say that we know little about this sponge. Topsent openly states (1900 

 p. 109): "je n'ai pas fait une étude anatomique approfondie de Spirastrella minax" . In 

 the second place it must be acknowledged, that the illustrations and the descriptions of the 

 spinispirae in the papers 1888 and 1900 are rather different. Externally the sponge does not 

 show anything in which it differs from other "species" of the genus. Nor do we find any 

 specific character in the arrangement of the spicules. Topsent states that S. iiiiuax "se distingue 

 de ces congenères par 1'ensemble de ses caractères : par sa forme encroütante et hispide, par 

 1'abondance excessive et par la configuration et les dimensions de ses microsclères". Novv we 

 have seen, that S. purpurea in the sense I take it is often encrusting, that the quantity of 

 spinispirae is exceedingly variable and that the same is true for the shape and size of these 

 spicules. True, all the specimens described to form thin crusts possess, in addition to minute 

 spinispirae, robust ones, whereas the encrusting S. miuax is said to possess minute spinispirae 

 only. This seems to be for Topsent the chief reason of separating his sponge from 5". cunctatrix. 

 But in this latter sponge the size of the large spinispirae is rather variable. Since we know 

 of many cases in which the number of large spinispirae is highly reduced, I think it hardly 

 advisible to consider 6". minax as a separate species. 



XX. Spirastrella cylindrica. 



1896 Kieschnick p. 534. 



1900 Thiele pp. 56, 60, 70. [PI. III, fi 



o\ 2 3 



The description given by Kieschnick is certainly inadequate. Thiele reexamined a specimen 

 with the result that he identifies it with S. vagabuuda. Indeed, as far as can be judged from 

 the descriptions 5. cylindrica seems to be something between S. vagabitnda and S. inconstans. 



XXI. Spirastrella atirivillii. 



1897 Lindgren p. 484. 



189S Lindgren pp. 322, 323, 370, 377. PI. 17, fig. II; PI. 18, fig. 4; PI. 19, fig. 22a — c, c', c" . 



According to the descriptions and illustrations Lindgren gives of this "species" the 

 Siboga specimens 1075 and 1403 fully agree with S. aurivillii. As these specimens are nothing 

 but young stages of trop. digitata I cannot accept Lindgren's sponge as a separate species. 



XXII. Spirastrella areolata. 



1897 Dendy p. 255 — 257. 



The largest specimen (dry) of Dendy's Spirastrella areolata is registered in the British 

 Museum '07. 8. S. 3; it bears my number B.M. 2- As it shows most distinctly the areolation 

 we may take this specimen as the type, and I have, therefore, illustrated it in tig. 4 on PI. III. 



