Olivek. — Mollusca of the Kermadec Islands. 545 



Heteroplocamus pacificus Bergh. 



Euplocamus pacificus Bergh, " Challenger " Rep., x, pt. 26, 57, 1884. 

 Recorded, Bergh, I.e. 



Habitat. — Dredged in 1,150 m., between Sunday and Macauley Islands, 

 on volcanic mud (" Challenger '* Expedition). 



Glaucilla atlanticus (Forster). 



Glaucus atlanticus Forster, Voy. " Resolution," i, 49, 1777. 



Habitat. — Live specimens frequently washed up on the beaches, Sunday 

 Island. 



Distribution. — Atlantic Ocean. 



Leuconopsis pacifica n. sp. Fig. 39. 



Description of Type Specimen. — Shell thin, ovate, apex obtuse. Whorls 4, 

 those of the spire flat, shouldered above, their sides nearly parallel, and, 

 as they decrease in size towards the apex, form a step-like series. Aperture 

 narrowlv pvriform. Outer lip thick in front, suddenly becoming thin 

 behind with a free rounded edge, thus forming a narrow posterior canal. 

 Inner lip a broad callous smear. Columella with 3 plaits, the central one 

 largest. Shell smooth with axial growth-lines, white. 



Height, 2-7 mm. Diameter, 1-5 mm. 



Variations from Type. — The upper columella plication, weak in the type, 

 is absent in all other specimens. The type is the largest specimen seen. 



Habitat. — Dead shells rarely found in dredgings in 10 m. to 30 m. off 

 Sunday Island. 



Melampus albus Oassies. 



Melampus albus Gassies, Journ. Conch., xiii, 211, 1865. 



Habitat. — Dead shells dredged on gravelly bottom near Sunday Island. 

 Distribution. — New Caledonia. 



Siphonaria. 



The representatives of this genus in the Kermadec Islands recall 

 Cellana in the multiplicity < 2 forms and the difficulty of dividing them 

 into specific groups with satisfactory limits. I have a good series of speci- 

 mens from Sunday Island, Macauley Island, and French Rock, and on 

 comparing them with what specimens are available to me from Norfolk 

 Island, New Zealand, Australia, and Tasmania I find that all appear to 

 be distinct from the species of those countries. The chief affinities lie with 

 Norfolk Island and New Zealand. I separate the Kermadec specimens into 

 four species. Here, as in Cellana, there seems to be some relation 

 between specific divergence on the one hand, and habitat and distribution 

 on the other, for the three principal species found at Sunday Island affect 

 distinct habitats, while the dominant forms on Macauley Island and French 

 Rock differ from each other and from those on Sunday Island. Hiding in 

 crevices of rocks near high-water mark on Sunday Island is the small 

 S. amphibia ; lower down the high and polished S. raoulensis occurs ; while 

 near low-water mark is found abundantly the remarkable S. cheesemani, 

 usually coated with crustaceous algae, and often adhering to the great shells 

 of Scutellastra kermadecensis. 



18— Trans. 



