l66 PORIFERA. II. 



6. L. complicata Arm. Hans. 

 PI. V, Fig. ii. PI. XVI, Fig. 4 a-g. 



1885. Reniera complicata Armauer Hansen, The Norwegian North-Atlantic Exp. XIII, Spongiadse, 7, 



PL I, fig. 8, PI. VI, fig. 8. 

 1885. Myxilla grisea Armauer Hansen, ibid. 12, PI. I, fig. 3, PI. VI, fig. 9. 

 1887. Clathria corallorhizoides Fristedt, Vega Exp. vetensk. Iaktt. IV, 460, PI. 25, figs. 73 — 77, PL 29, 



fig- 23. 



Erect, busJi-sliaped, with more or less, often highly anastomosing branches. The surface shaggy. 

 The dermal membrane a very thin film with partly projecting, partly horizontal dermal spicules. The 

 skeleton a somewhat irregular network; primary, polyspicular longitudinal fibres arc found, bending 

 gradually tovuards the surface; they are connected by irregularly placed, mostly single transverse spicules. 

 Spicula: Mcgasclcra : the skeletal spicules smooth styli 0-4.2 — o-6S""", the dermal spicules strongyla to 

 subtylofa 0-22 — 0-40"""; microsclera of three forms, chela- arcuata 0-04 — 0-058'"'", sigmata of two forms, 

 small ones o-oiy — o-02j mm , large ones 0-042 — 0-055""". 



This species has a beautiful and characteristic outer form, and in this respect it recalls the 

 Clathrise. It is markedly bush-shaped; from a small base of attachment a number of branches issue, 

 rising and ramifying and anastomosing copiously. Especially the anastomoses are numerous and lead 

 to the forming of plate-shaped parts pierced by larger or smaller holes, so that only the outermost 

 short branches are free. The tendency to plate-shaped coalescing is also seen by the fact that 

 the branches are not cylindrical, but more or less compressed. The species may in this respect be 

 somewhat varying, the branches in some individuals being comparatively free, while in others they 

 are quite coalesced, so that the question is really not of branches, but of anastomosing curled lamellae. 

 As mentioned above, the base of the sponge is comparatively small, and sometimes a short stalk is 

 formed. The largest specimen in hand has a height of 85™", a greatest breadth of ca. ioo mm , and a 

 breadth at the base of 30"™. The outermost, free parts of the branches have a thickness of ca. 4— 8 mm . 

 Then we have specimens in decreasing sizes, the smallest one, which seems to be entire, has a height 

 of ca. 25 mm . None of the specimens are attached, but in several of them loose bottom material is found 

 on the basal surface, so that the sponge seems to have grown directly on the bottom. The colour (in 

 spirit) is light yellow or whitish yellow, sometimes more gray, which latter I take to be due to the 

 sponge containing sand. The sponge has a characteristic, net-like appearance, such as is found in 

 many Reniera-species, which is due to the fact that the mouths of the close-set canals under the 

 dermal membrane are seen shining through the membrane as dark spots. The consistency is firm and 

 elastic. The surface is very shaggy from projecting spicules; some individuals may be more shaggy 

 than others. The dermal membrane is an exceedingly thin and transparent film resting on the skeleton 

 below and supported by dermal spicules. Pores and oscula: the pores are found in the dermal mem- 

 brane, frequently gathered in sieve-like areas, but also in other places singly and much scattered; they 

 are circular or oval. Their size was measured to ca. 0-012 — o'3 mm . Then some larger, round or oval 

 openings are found, sometimes closely gathered, sometimes more scattered. Their size may vary from 



