Stat. 127. Taruna-bay, Great Sangir-island. Reef, i Spec. 

 Stat. 231. Amboina. Reef. 6 Spec. 



This easily recognized species, distinct by its very flattened shape, its striated surface and 

 large dimensions, should belong to the subgenus Gena s. str.. Fischer (Manuel de Conchyliologie 

 etc., Paris, 1887, p. 840) has proposed the new subgenus Plomacotis for G. laevis Pease and its 

 allies, on account of the presence of epipodial cirri, which should be wanting in G. planiUata, 

 nigra and bitea, according to the researches of Ouoy and Gaimard, moreover G. laevis should 

 possess a siphon on each side of the neck. Now in the specimens of the Siboga-expedition 

 from Amboina, I see distinctly those siphons, though much shorter by the contraction in alcohol, 

 and in one of them, I find on the right side, 3 epipodial cirri, accompanied by a lobed appendage 

 and one distinct cirrus on the left side ; in the other specimen the cirri are scarcely or not at 

 all visible, and so former observers may have failed to perceive them. In most other respects 

 the description of the soft parts agrees with that of G. laevis, for though I cannot detect that 

 the tentacles and eye-stalks are hirsute, this may depend on contraction. One of the specimens 

 from Amboina, and from Stat. 127 have lost their tails. 



Though Lamarck (1. c.) has cited the figure of Rumph for Stomatella atiriaila, it is not 

 doubtful that Rumph has had in view G. plamilata, his figure and short description, with the 

 rerriark that they have scarcely a length of a phalan.x of a finger, agrees only with this species, 

 the more so, if one looks at the long fingers of that author on his portrait in the "Rariteitkamer". 



2. Gena nigra Quoy & Gaimard. 



QuoY & Gaimard. Voy. de 1' Astrolabe, III, p. 307, PL 66 bis, figs. 10 — 12. 

 PiLSBRY. Man. of Conch. Vol. XII, p. 38, PI. 51, fig. 20, 21. 



Stat. 301. Pepela-bay, East coast of Rotti-island. Reef, i Spec. 



The only shell from the named locality agrees sufficiently with the description and figures, 

 it is blackish with a few very small white dots. 

 Long. 167,, lat. 8 Mill. 

 (See also Appendix). 



3. Gena lintrictila Adams. 



A. Adams. Proc. Zool. Soc. Lond. 1850, p. 38. 



Reeve. Conch. Ic. Vol. XIX, Gena, fig. i. 



PiLSBRY. Man. of Conch. Vol. XII, p. 44. ?!• 55. fig- H- 



Stat. 144. North of Salomakie-(Damar)-island. 45 M. Coralbottom and Lithothamnion. i Spec. 



The specimen differs from the original description in colour; the posterior part of the 

 shell is nearly entirely yellowish-white with a green tinge, moreover a few smaller patches of the 

 same colour are dispersed over the anterior part, a few dark spiral lines are more conspicuous 

 on the posterior part. The surface is covered with very fine, close-set spiral and by more remote 

 concentric striae. The species may be easily recognized by its very elongate shape. 



81 



SIHOGA-EXPEDITIE XLIX' rt. II 



