THE MOLLUSCA HEDLEY. 



425 



I found this gregarious species in great numbers under stones 

 between tide marks on the lagoon shore of Funafuti. Tenison 

 Woods has described this as occurring in similar positions and 

 abundance in tropical Queensland.* 



In this Museum it is represented from Torres Straits and Port 

 Molle, Queensland, and the Solomons. 



PLANAXIS LINEATUS, Da Costa. 

 Tryon, loc. cit., p. 278, pi. liii., figs. 49 - 57, 59, 63-66; pi. lii., figs. 



38 - 48. 



This species is also markedly gregarious. Little colonies 

 occurred under stones between tide marks on the outer reef of 

 Funafuti. 



Tryon mentions this from the Solomons, Tahiti and Paumotus. 

 Melvill and Standen record it under the synonym of P. viraatus, 

 Smith, from Lifu. Smith gives it from Fiji.f I have collected it at 

 Oubatche, New Caledonia, and this Museum has it from Hawaii and 

 the New Hebrides. 



MELANIA MAGENI, Gassies. 

 Gassies, Faune Conchyliologique de la Nouvelle Caledonie, 1863, 



part i., p. 95, pi. vi., fig. 10. 

 Abundant in the native wells at Funafuti. 

 First described from New Caledonia, and lately recognised by 

 Smith from Rotuma. Contrary to the priority given by Brot 

 and Crosse this species has page precedence over M. montrouzieri, 



CAECUM VERTEBRALE, sp. nov. 

 (Fig. 15). 



Caecum sp., De Folin, Challenger Reports, Zoology, 

 xv., 1886, p. 684, pi. ii., fig. 12. 



Shell of moderate size for the genus, white 

 (? bleached), rather curved, slightly tapering, 

 ornamented with twenty-five strong, pretty regular 

 rounded, transverse rings, which are separated by 

 interstices of corresponding breadth and depth. 

 Septum a low rounded dome. Length 2-15, 

 breadth -56 mm. 



A single perfect specimen, gathered on the sandy 

 shore of the lagoon, is with some confidence identi- 

 fied with a nameless fragment dredged by the 

 "Challenger "off Honolulu. 



Fig. 15. 



* Tenison Woods Proc. Linn. Soc. N. S.W., v., 1881, p. 108. 

 f Smith Journ. Linn. Soc., Zool., xii., 1876, p. 552. 



