408 PROF. J. A. THOMSON AND MR. W. D. HENDERSON ON [Apr. 10, 



expansion becomes thin-walled and is readily ruptured. The 

 embryos appear as elongated lemon-shaped bodies, 1 mm. in 

 length by 0'75 in maximum diameter. Theie are numerous ova 

 on the mesentei'ic bands. It may be suggested that the expansions 

 figured by May in C. longissima and G. strumosa are also repi'o- 

 ductive swellings. 



Locality. Wasin Channel, 10 fathoms. 



Sympodium punctatum May. (Plate XXIX. fig. 9.) 



A specimen spreading over a monocotyledonous leaf agrees on 

 the whole with the description which May gives of S. 2nmGtatum. 

 There are two sets of spicules — the upper layer whitish, the lower 

 layer deep red. The spicules are about 0"2-0'o mm. in length ; they 

 are fundamentally of the spindle-type, but bear ii'regular warty 

 piocesses, often with sharply truncate ends. The white spicules lie 

 irregvilarly in an almost continuous superficial coveiing ; the 

 deeper red spicules are partly interlocked by their warty, often 

 bi'anched j)rojections. The colour scheme is slightly difierent 

 fi-om that of May's specimen, since the red spicules are almost 

 entirely confined to the basal membrane. 



Locality. Ohuaka shore, low spiing-tide. Previously from 

 Tumbatu. 



Sympodium cceruleum Ehrenberg. 



To this species we refer several rather poor specimens " of a 

 sea-green colour,"- with polyps which can be completely retracted. 

 The basal membi'ane is a broad plate, 33 mm. in maximum length 

 and 16 mm. in maximum width. It is thin at the edges, but 

 1 mm. in thickness near the middle. 



The polyps have shoi't tentacles on which the finger-shaped 

 pinnvdes are arranged in one row on each side, about 15 in each^ 

 row. 



There is no trace of the calcareous bodies which Klunzinger 

 figures ; there are abundant zoochloi-ellfe. The co3nenchyma of 

 the colony is hyaline and non-granular. 



Locality. Previously from Tumbatu, Red Sea. 



Sympodium fuscum, sp. n. (Plate XXX. fig. 5.) 



A spreading colony, forming lai-ge flexible sheets attached to 

 basal parts of Zostera. The living specimens wei-e reddish bi-own 

 all over, except the tentacles which were drab-brown ; the pre- 

 served specimens are creamy-white. 



The'"stolon is a membranous plate from 2-3 mm. in thickness, 

 rather thinirer at the edges. The polyps are uniformly distri- 

 buted over the surface, and are capable of complete retraction 

 into the stolon, thus giving it a porous appeai-ance, somewhat 

 honeycomb-like. The pores have a diameter of 1 mm., and are 

 about 0"5 mm. apart. Spicules are numerous in the stolon, and 

 form a superficial network, in the meshes of which the polyps 



