REPORT ON THE MONAXONIDA. 121 



lophon laminalis, Eidley and Dendy (PI. XVI. fig. 6 ; PL XVII. figs. 9, 11). 



1886. lophon laminalis, Eidley and Dendy, Ann, and Mag. Nat. Hist., ser. 5, vol. xviii. p. 349. 



Shape doulitful. In its present condition the specimen consists of a number of 

 irregular, flat, or slightly curved, cake-like expansions (PI. XVI. fig. 6), which, taken 

 together, cover an area of about 250 square centimetres. These have no appearance of 

 having lain on the bottom of the sea, and a.s they seem too thin and fragile to have 

 stood erect as a flat lamina, we are inclined to think that, when living, the sponge had 

 a cup-like form, like Alehion {lophon) piceum, Vosmaer,^ from Barents Sea, Thickness 

 of the lamellje 4 to 17 mm. The two sides are slightly difierent in appearance, 

 one being smoother than the other. There is a distinct, thin, dermal membrane, 

 especially visiljle on the smooth side. Colour in spirit dark reddish-brown. Surface 

 uneven, with numerous small oscula scattered over it on both sides of the lamellae. 

 Texture loose, crumbling, slightly stringy. 



Skeleton. — (a) Dermal; a network (not always easy to make out) of tylota. [h) 

 Main; a loose reticulation, not arranged in definite meshes, of large, subtylostylote 

 spicules arranged longitudinally along certain tracts, so as to form long but loose fibres, 

 which give rise to the somewhat stringy character of the sponge. 



Spicules. — (a) Megasclera ; (l) large subtylostyli (PI. XVII. fig. 11, h), measuring 

 0'63 by 0"022 mm. The heads of these spicules are only faintly developed, so that 

 they are very nearly simjjly stylote, and they taper somewhat suddenly, from near the 

 apex, to a sharp point. (2) Tylota (PI. XVII. fig. 11, a), shaft and head usually smooth, 

 but head sometimes minutely spined; size 0'34 by O'OOIS mm. (6) Microsclera ; two 

 kinds are present as usual, (l) Palmate anisochelse, 0'025 mm, long; (2) bipocilli 

 (PI. XVII. fig. 9) 0'013 mm. long The palmate anisochelse seem to be very rare in the 

 one specimen present ; but the bipocilli are extremely abundant and very fine, consisting 

 each of a curved shaft with a large cup-shaped expansion at one end and a small one at 

 the other. 



Only one specimen, broken into fragments, of this interesting species was obtained. 

 In the fine state of development of its bipocillate microsclera it approaches lophon 

 chelifer, a specimen of which was obtained at the same station ; while in external form 

 it probably comes near to lophon piceum, Vosmaer.^ The species to which it is perhaps 

 most nearly related is, however, lophon cylindricus, which, like it, has the stylote 

 spicule smooth ; but, as will be seen from the description of that species, the projaortions 

 of the spicules in the two differ very widely; and, as in probably no other known lophon, 

 the styli here show a tendency to become tylostylote. 



ioca/%.— Station 145a, December 27, 1873 ; lat. 46° 41' S., long. 38° 10' E.; off 

 Prince Edward Island; depth, 310 fathoms; bottom, volcanic sand. One specimen. 



1 Niederland. Archiv f. ZooL, Suppl. Bd. i., 1881-2, p. 42, pi. i. fig. 19, pi. iii. figs. 75-82. 

 ' Loc. cit., swpra, pi. i. fig. 19. 

 (zooL. CHALU EXP. — PAET Lix. — 1887.) Nnn 16 



