BY C. HEDLEV. 703 



A similar arrangement of the epipodium, entire on the right, 

 slashed in tatters on the left, is shown by Trochus pica* and 

 T. lineatus.j 



Gena strigosa a. Adams. 

 (Plate xlvii. fig.ll.) 



Gena strigosa A. Adams, Proc. Zool. Soc, 1850, p.37 ; Id., 

 Sowerby, Thes. Conch., ii., 1854, p.830, P1.173, figs.ll, 12 ; Id., 

 Angas, Proc. Zool. Soc, 1867, p.218. Gena nigra Brazier, Journ. 

 of Conch., vi., 1889, p. 72 (not of Quoy & Gaimard). 



Mr. T. Iredale was kind enough to compare critically a series 

 of specimens from Sydney with the unlocalised types, three 

 specimens, of G. strigosa in the South Kensington Museum. He 

 reports that my set agreed with types in size, shape, and general 

 colouration; and concludes that Gena strigosa is the correct name 

 for the Sydney species. He also considers that it does not, as 

 has been indicated, extend to the tropical Indian Ocean. 



Tlie favourite haunt of this animal is under rather large 

 boulders in the Hormosira-zone. It crawls rapidly, seeking 

 always to escape from the light. Behind the shell, the large 

 muscular foot extends for more than half the total length of the 

 animal. It is liable to break off by self-mutilation just behind 

 the shell, if the animal is annoyed. It is covered with small, 

 large, and sometimes compound tubercles. The shell is wholly, 

 or partly, overspread by the large mantle, also bearing small and 

 branched processes. Thin, smooth lobes of the mantle protrude 

 on the right and on the left as a scoop or pipe, acting as siphons. 

 Posterior to these are epipodial lobes, three on each side, re- 

 tracted and exserted from pockets. Beside each lash arises a 

 conspicuous branched process, apparently the homologue of the 

 stump of Monodonta. As is usual when tlie foot is so tubercular, 

 the epipodial line is indistinct. In addition to the three lateral 

 filaments, the epipodium is displayed above the muzzle as a 

 slashed fringe, sometimes separate, sometimes united. Cephalic 

 tentacles long and slender, each with an external ocular stump. 

 A] uzzle broad and produced, fringed towards the neck. 



* Fischer, Coq. Viv., 1880, PI. i. 

 t Randies, Quart. Journ. Micro. Sci., xlviii., 1904, PI. iv., fig. 7. 



