6 AETEID.^. 



the spatulate extremity is beautifully ringed. Mr. Busk 

 has noticed the pouch " like the bag of the pelican's beak/' 

 which is formed by the membranous covering of the aper- 

 ture^ and remarks that numbers of Naviculee and Infusoria 

 are often found in it. The polypide^ which is small and 

 delicate, has usually twelve tentacles of moderate length. 

 When the oral valve opens, a membranous sheath is first 

 pushed out, with a number of setiform processes round 

 its free extremity, which are thrown back and form a kind 

 of frill ; and then the polypide instantly darts forth : little 

 more than the pharynx and tentacular crown is protruded. 



The swellings on the creeping base in this species are of 

 moderate size, and generally occur at short intervals ; so 

 that the cells are set pretty closely together. 



Aetea anguina is developed in extraordinary profusion ; 

 and bunches of weed are often so thickly covered with 

 it as to appear powdered over with white. Masses of 

 Algse from Australia are invested in a similar way by the 

 kindred A. dilatata. 



Aetea recta, Hincks. 



Plate I. figs. 6, 7. 



HiPPOTiioA SKA, Couch, Corn. Faun. 102, pi. xis. fig. 9 : Johnston, B. Z. 



ed. 2, 292. 

 Aetea recta, Hincks, Devon Cat., Ann. N. H. ser. 3, ix. 25, pi. vii. fig. 3. 

 STOMAToroRA Gallica, D'Orbigny, Pal. Fran^. Terr. Cret. v. 836, pi. 759, 



figs. 1-3. 

 Aetka sica, Norman, Quart. Jouru. Micr. Sc. n. s. viii. 216. 

 Aetea anguina /3, forma recta, Smitf, Gifvers. K. Yet.-Akad. Forhandl. 



1867, No. 5, 281 & 297, pi. xvi. figs. 5, 6. 



Zoacia tall, nearly straight, very slightly dilated above, 

 truncate at the extremity ; surface coarsely ringed 

 below, the upper portion punctulate; area elongate, 

 occupying more than a third of the length of the cell ; 



