PLEUROBRANCHUS, HALIOTINELLA. !>()!) 



behind like the foot, borders of mantle and foot not projecting be- 

 yond each other. Penis not visible externally. Small black eyes 

 at bases of the tentacles ; tentacles blunt in front. Gill with 23-25 

 branches. Length one inch. 



Shell lying in about the middle of the back under the mantle, 

 but a little toward the right over the gill ; very small but relatively 

 thick, calcareous, narrow and white behind, wider and reddish- 

 brown in front, resembling the shell of Pinna in respect to contour. 

 Consists of united layers. Length 2 lines. (It. & Z,.). 



Gulf of Suez, on the shore; collected in February. 



Pleurobranchus citrinus R. & L., Atlas zu der Reise im Nord- 

 lichen Afrika von Eduard Riippell, Neue Wirbellose Thiere des 

 Rothen Meeres, p. 20, pi. 5,f. 1 (1828). EHRENBERG,.Symb.Phys. 

 Decas 1, No. 1. ISSEL, Mai. Mar Rosso, p. 162. ?SowERBYin 

 Reeve, Conch. Icon., xvii, pi. 1, f. 7. Probably not P. citrinus? 

 KELAART, Ann. Mag. Nat. Hist. (3), iii, p. 495. 



Sowerby gives a figure of the shell, said to be copied ; but he mis- 

 quotes Riippell's page and figure, and there is no illustration of the 

 shell in Riippell's work. 



P. ZEYLANIC T JS Kelaart. Unfigured. 



Pale yellow, splashed with darker yellow and brown, and minutely 

 spotted with rusty brown. About 2 inches long. (KeL). 



Hack Bay, Ceylon (Kel.). 



Pleurobranchus zeylanicus KEL., Ann. Mag. Nat. Hist. (3), iii, p. 

 495 (1859) ; Journ. Ceylon Branch Roy. Asiat. Soc., iiis pt. 1, p. 



Ill (1883). 



? Genus HALIOTINELLA Souverbie, 1875. 



Shell umbilicated, auriform, with an epidermis, thin, much de- 

 pressed ; spire posterior, very short, many whorled ; whorls few, the 

 last very ample, forming the greater part of the shell ; aperture 

 very large, the margins not joined, left margin inflexed below, re- 

 flexed at the columellar insertion ; soft parts unknown. (Souv.). 



The genus was provisionally placed by Souverbie in the vicinity 

 of Sigaretus. Morch declares it to be based on a Pleurobranchus 

 shell ; and Fisher locates it with doubt in Pleurobranchidce. I am 

 disposed to agree with the view expressed by Morch. 



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