Tritonia.} GASTROPODA. 555 



Fam. TRITONIID.SJ, Adams. 



The bodv is elongated and .slightly quadrangular, the anterior 

 portion is broader, the posterior narrowed ; the dorsal surface is 

 flattened and granular in appearance ; the sides of the body are high 

 and perpendicular ; the foot is broad. At the anterior extremity the 

 back acquires a crescentic prominence, the frontal veil ; the free margin 

 of this is covered with small papillae, or with simple, sometimes com- 

 pound, finger-shaped processes ; the outer extremity is thickened, 

 and forms a spoon-shaped structure, the tentacle proper. The rhino- 

 phores are situated on the neck, just behind the frontal veil. The 

 sheath of the rhinophores is tubular and slightly depressed, with 

 a recurved margin ; the sword-knot-shaped club is retractile, the 

 central portion has a flattened upper surface, the margin is set with 

 erect feather-like processes, the rhachis of the hindermost process is 

 continued into a rather strongly developed papilla. On the slightly 

 prominent margin of the back there are a number of variously sized 

 branchial tufts, arranged one behind the other in a single series ; 

 they are low, more or less arborescent, tri- or quadri-pinnate, and 

 are set on a short stalk. The anal papilla and the renal aperture 

 are situated close to each other about the middle of the body, on the 

 right side. The foot is rather broad and rounded at its anterior end ; 

 the tail is very short. 



There are 2 well-developed jaws. Radula with a central tooth, 

 on each side of which is a series of uncinate teeth ; the first lateral 

 tooth always differs from the rest. 



The Tritonidce are carnivorous animals, feeding chiefly on Alcyon- 

 arians and allied forms. 



Distribution. Seas of Europe, Red Sea, Pacific, Cape of Good 

 Hope, Brazil, New Zealand. 



Genus 1. TRITONIA, Cuvier, 1798. 

 Tritonia, Cuvier, Tabl. Element., 1798, 387. Type : T. Hombenji, Cuv. 



Sphazrostoma, Macgillivray. Liriope, Gist. Candiella, Gray. 

 Body prismatic, often thick and firm. Rhinophores 2, ramose 

 and filamentous, more or less brush-shaped, retractile within tubular 

 sheaths. Head with a tuberculated or digitated veil. Branchial tufts 

 ramose, arranged in a single series along the ridge bordering each 

 side of the back. Mouth armed with 2 horny jaws. Central tooth of 

 radula large, depressed, subpyramidal, the first lateral tooth of the 

 same form as the central, the others uncinate. Stomach unarmed. 



The genus is probably cosmopolitan, but specially frequent in 

 colder seas. (Eliot.) 



1. Tritonia incerta, Bergh, 1904. 



Tritonia incerta, Bergh, Reise Philipp., ix, Malacolog. Unters., pt. 6, 1904, 

 24 ; Benham, T.N.Z.I., xxxvii, 314. 



Animal having the form usual in the genus. The buccal veil carries 

 altogether 7 finger-shaped lobes. The tentacles have the usual form. 



