HuTTON, — On some Branchiate Mollusca. 163 



Dentition. The centfal tooth is cui'ved, rather swollen at each end, its 

 breadth four times its length ; it has three equal denticles in the middle on 

 its anterior surface. The lateral teeth have two denticles, the outer being 

 the longer, and more curved ; they lie distant from the central tooth, 

 (PI. VI., fig. c.) 



The specimen from which the drawing was made was obtained at 

 Sumner. 



CoLUMBELLA CHOAVA. Animal yellowish white, with a narrow black 

 longitudinal line on the back of the head, between the eyes ; some scattered 

 dead-white spots on the body and siphon. Tentacles thick, not tapered, . 

 approximated ; the eyes at their outer bases. Siphon curved. Foot ex- 

 panded in front, and notched at each side. No operculum, (PI. VII., fig. o.) 



Dentition. 1-0-1 ; the central portion of the radula is thickened, and 

 divided transversely into membraneous plates, which are broader than long, 

 but the plates bear no teeth. The lateral teeth are versatile ; they are 

 curved, pointed at the end, and with two small denticles on the concave 

 side. (PI. VII., fig. p.) 



This species occurs occasionally on seaweed in Lyttelton Harbour. I 

 described the animal in the " Transactions of the New Zealand Institute," 

 vol, xiii., p. 201, by mistake, under the name of Defranchia luteo-fasciata. 



Stkuthiolaria papulosa. The dentition is remarkably like that of 

 Trochita. The radula is delicate and short, with only about 24 transverse 

 rows of teeth. The central tooth has a quadrate base ; the reflected portion 

 is triangular, rather longer than broad, and denticulated on each side. The 

 first lateral has a breadth of nearly twice its length, and the short reflected 

 portion is slightly denticulated on the margin. The second and third 

 laterals are nearly similar, but the base of the second is rather broader and 

 squarer than that of the third ; they are versatile. Both are long and 

 curved, the apex blunt and slightly bent over ; both are denticulated at the 

 end and on either side near the apex, the denticulations stronger on the 

 outer side. (PI. VI., fig. h.) 



In the male the denticulations are stronger than in the female, in all 

 other respects they are alike. The drawing is taken from a specimen col- 

 lected at Nelson by Mr, J, D, Enys, in it the teeth are separated to show 

 their form. In their proper position the apices of the second and third 

 laterals nearly meet in the centre. The breadth of the radula is -019 inch, 

 and its length about -07 inch, in a full-sized specimen. 



Trochita nov^-zealandi^. Dentition. The radula has about 44 trans- 

 verse rows of teeth ; the second and third laterals are versatile. The 

 central tooth has a broad rounded base, the reflected has a median cusp 

 with four small denticles on each side ; the cusp has a sharp cutting point. 



