6 



reddish colour, surrouudiiig a .siliceous rod, wliicli is from 2-3 mm. in Itrcadth aud 

 300 mm. in length. The average breadth of the colony, polyps included, is 

 22 mm., of the coenenchyma, apart from the polyps, 8-12 mm. At the basal 

 end of the colony the rod is left bare for 50 mm. There can be little doubt that 

 this rod, wliich serves as an extrinsic support to the colony, is an immense sponge 

 spicule, such as has been described in Moiiorhaphis. 



The colony consists of about 75 large slightly-retractile autozooids, 

 10-12 mm. in height, about 4 mm. in diameter, and witli tentacles 

 3-5 mm. in length. These autozooids arise from the finely granular 

 coenenchyma, apparently without regular arrangement, at intervals of 2-G mm., 

 and on all sides. The spaces between them are covered with very numerous 

 siphonozooids. 



Extending in a spiral up the siliceous rod there is a broad (2 '5-4 mm.) band 

 of thin coenenchyma, which bears neither autozooids nor siphonozooids. At six 

 places the opposite margins of thick polyp-bearing coenenchyma arch over the 

 thin coenenchyma and come into contact ; at two other places the thick cceuen- 

 chyma completely surrounds the rod. It may be suggested that the Inroad liare 

 band corresponds to the stalk. 



Along each margin of the thick coenenchyma as it abuts on the bare tract, 

 there is a row of minute autozooids (about 1 mm. in diameter) with brownish 

 tentacles, and between these and the typical autozooids there are many inter- 

 mediate sizes. The minute marginal autozooids are separated by intervals, 

 varying from l-2"5 mm. 



The surfiice of the coenenchyma appears to be covered by minute .spiculated 

 warts, which mark the apertures of the siphonozooids. Between the ccenenchyma 

 and the siliceous rod there is a thin film of faintly yellowish debris. 



The autozooids have a much wrinkled surface, due to contraction. The 

 tentacles are simply infolded, and bear 12-15 plump conical pinnules. The 

 tentacles have large cavities flattened in the radial plane, their aboral surface (in 

 the preserved state, at least) is a narrow ridge bearing longitudinal rows of 

 spicules. In one case a tentacle was seen to be completely inturned into the 

 stomodasum. The wall of the stomodseum is substantial, and transversely 

 annulated, recalling a similar appearance in Sarcophyhmi agaricoides. It is 

 continued inwards below the surface of the coenenchyma, almost as far as the 

 .siliceous rod. 



A slice parallel to the surface of the ccenenchyma exposes the crowded cavities 

 of the siphonozooids, usually about 075 — 1 mm. in diameter, and are at once 

 seen to be crowded with ova (0"3 mm. in diameter) and jjlastula emhryos 

 (0"5 mm. in diameter). In some cases gastrulation had occurred. 



A section in the plane of the longitudinal axis of the minute marginal 

 autozooids at one of those regions where the opposite margins of thick coenenchyma 



