66 PORIFERA. II. 



thorns (Lambe). Also this species seems to be a native of the cold bottom ; to be sure, a bottom 

 temperature of 4°8 C. is stated for station 44; but in its immediate neighbourhood, on station 43, so 

 low a positive temperature as o°5 C. is found. 



It is worthy of notice that in the three species of the subgenus Asbestopluma and the two 

 Lycofodina-apecies now treated, which are in all principal respects of the same outer form, the skeleton 

 of the axis is formed in a somewhat different way. In pennatula only few spicules are found in the 

 middle of the axis, and also between the canals only narrow spicula-parts occur; outermost, on the 

 other hand, there is a powerful spicula-layer, to which the firmness of the axis is especially owing. 

 In bihamatifera a circle of powerful fibres is found, and outermost only a thin spicula-layer. In furcata 

 the axial skeleton is divided into more or less narrow spicula-parts, and outermost is found a rather 

 powerful spicula-layer. In cupressiformis we find a strong skeletal axis situated in the middle, the 

 spicules of which may be more or less gathered into fibres, which are then connected by a network 

 of not parallel spicules. In lycopodium, finally, there is a circle of separate fibres, and here no spicula- 

 layer is found outermost. 



6. A. hydra n. sp. 

 PI. II, Figs. 18, 19. PL XI. Fig. 8 a— f. 



Formed like a tree with brandies issuing from the upper end of a stalk. The skeleton consists 

 in the stalk of a spicula axis, in the upper end of which the fibres of the branches are inserted. Spicula: 

 Megasclera subtylostyli, in the axis 077 — o-S""". in the branches 0-35 — o-6o'"'"; microsclera of one form, 

 anisochehr palmatcr of the characteristic type 0-012— 0-014""". 



This small Lycopodina-sptcies is of an exceedingly beautiful and elegant form. It consists of a 

 stalk ending in a swelling above, from which issues a number of thin, undivided branches. Below it 

 is by an expanded basal part attached to a small stone, a lump of sand, or the like. The stalk is 

 cylindric and straight. The sponge is of small size, the largest specimen is i2 mm high, and the greatest 

 length of the branches is 4— 5 mm . The stalk is only ca. o-i5 ,nra thick, and the branches ca. 0'C>5 mm . 

 The smallest specimen is 5 mm high. The branches may be of somewhat varying length, and in a few 

 cases they are quite short or almost wanting. In the latter case the upper side of the swelling is 

 densely shaggy from projecting spicules, which, as far as I have been able to decide, belong to the 

 thinner form, occurring in the branches. The swelling, from which the branches issue, seems also to 

 be always larger and more compact, when the branches are quite short or wanting, than when they 

 are present in their full length; therefore I am also here inclined to think that the branches are able 

 to contract. The consistency is firm, as the greater part of the sponge consists of spicules with com- 

 paratively little soft tissue, but the sponge is flexible and elastic. The colour (in spirit) is white or 

 slightly whitish yellow. The surface is smooth on the upper part of the stalk and the branches, only 

 in the ends of the branches the spicules project. The lower part of the stalk and the basal expansion 



