Amphibola.] GASTROPODA. 597 



Anatomy. --Lehmann, Malak. Blatt,, xiii. 1866, 111; Hutton, 

 A.M.N.H. (5). iii, 1879. 181, pi. 22. 



Dentition. Button. T.N.Z.I., xiv. 156, pi. 4, f. F. 



Type lost. 



Hob. Most estuaries of New Zealand. Brought to England by 

 Captain Cook. 



The animal lives between tide-marks in salt or brackish water on 

 mud-flats in sheltered bays. When found at all, it is always found in 

 large quantities. ' It is very sluggish in its habits, and feeds on the 

 vegetable matter contained in the mud, passing large quantities 

 through its alimentary canal. Although air-breathing, it will live for 

 a week or ten days in fresh water, and for more than a fortnight in 

 salt water, without being exposed to the air. (Hutton.) 



Remarks. The animal is eaten by Maoris and many white people. 



Maori. Titiko (fide Captain Bollons). 



Fossil. Post-Pliocene. 



Fam. SIPHONARIID.E, Adams. 



Animal having the head expanded, the tentacles atrophied, bilobed 

 in front ; eyes sessile on the outer sides of the disc. Visceral mass 

 conical. Genital orifices contiguous. Respiratory orifice covered by 

 a large fleshy lobe of the mantle. Aquatic pallial cavity containing 

 secondary branchial laminae. No operculum. Marine. Jaw arcuate, 

 with simple or projecting margin and with vertical filaments above. 

 RaduLa broad, rather long ; teeth numerous, equal, in slightly arched 

 transverse lines. Central tooth narrow, elongated, with a small 

 rhombic apex ; lateral teeth larger, diverging, gradually diminishing 

 in size outwards. 



Shell conical, patelliform, muscle - impression interrupted by a 

 lateral groove on the right side corresponding with the pulmonary 

 orifice. 



Genus 1. SIPHON ARIA, Sowerby, 1824. 



Siphonaria, Sow., Genera Rec. & Foss. Shells, pt. 21, Jan. 3, 1824. First 

 species : 8. sipho, Sowerby. 



Animal having the head large, flattened, divided into 2 equal 

 rounded lobes, the small eyes on their upper surfaces. Pulmonary 

 orifice on the middle of the right side, in line with the anal opening. 

 Central tooth of radula unicuspidate, laterals bicuspidate, and the 

 marginals tricuspidate, short, transverse. 



Ova in white gelatinous rope-like masses, attached to rocks in 

 irregular curves, much like ova of Nudibranchs. They may be found 

 early in February, sometimes in great abundance. 



Shell solid, inside polished, summit central or subcentral. Muscle- 

 impression horseshoe - shaped, the anterior ends united by a groove 

 corresponding to the line of attachment of the mantle to the shell ; 

 it is interrupted on the right side by a deep siphonal groove, which 



