Ortfhiddla.] GASTROPODA. 811 



3. Onchidella irrorata, Gould, 1852. 



Peronia irrorata, Gould, U.S. Expl. Kxp., xii, 1852, 291 ; atlas figs. 383, a, b. 

 Onchidium (Peronia} irroraia, Gould, CVit. List, 39. Onchidella irrorata. 

 Gould, M.N.Z.M., 28 : Filhol, Miss. T.C., 521. 



Elongated, oval, back arched, margins expanded, mottled olive 

 and yellow, finely covered with minute subequal granulations, with 

 8 or 10 elevated radiating folds or ridges at the margin on each side, 

 which extend a little beyond the margin and give it a dentate appear- 

 ance ; head scarcely protruding beyond the body, dilated at the 

 anterior angles ; tentacles short, slender, blue, knobbed, and with an 

 eye-spot at the tip ; head above pale sky-blue, and also the mantle 

 surrounding the foot ; margin beneath ochreous ; foot a little more than 

 one-third the width of the body. (Gould.) 



Length, 25-5 mm. ; breadth, 13 mm. ; height, 6 mm. 



This species may be compared with P. patelloidea, Q. & G., which 

 is also from New Zealand ; but, if the figure is to be relied on, it 

 is certainly different, the colour, form, number of marginal projec- 

 tions, &c.. being all different. (Gould.) 



Type in the U.S. National Museum, Washington. 



Hob. Found in tide-pools at low water. Bay of Islands, New 

 Zealand (Drayton) ; Cook Strait (Filhol). 



Remarks. This species has to be re-examined, and I tried to get 

 specimens from the Bay of Islands, but failed. 



In the diagnosis of Gould there is hardly anything that would 

 separate his species from 0. patelloides, which has always 19 to 20 

 marginal glands. I also think that the specimens found by Filhol 

 in Cook Strait, and plentiful in Massacre Bay, were 0. patelloides. I 

 have not seen Gould's figures. 



4. Onchidella nigricans, Quoy and Gaimard. 1832. Plate 32, 

 fig. 3. 



Onchidium nigricans, Q. & G., Voy. Astrol., Zoo!., ii, 1832, 214, pi. 15, 

 f. 24-26 ; Dieff. N.Z., 248 ; Crit. List, 39. Onchidella nigricans, Q. & G. : 

 Chenu, Man. Conch., i, 474, f. 3506 ; Button, C.M.M., 54 ; M.N.Z.M., 28. 

 Oncidiclla nigricans, Q. & G. : Wissel, Zool. Jahrb., Syst., xx, 1904, 662, 

 pi. 25, f. 70-74 (animal, anatomy). 



Animal oval, back slightly elevated, broadly keeled above, black 

 with white marginal glands ; tentacles thick and short, rounded into 

 a button at their extremity. Sculpture : The whole of the notum 

 covered with minute granules, amongst them a number of slightly 

 larger ones ; young specimens have very often the centre of the back 

 more or less smooth, with a few distant papillae only ; the number of 

 the marginal glands varies from 16 to 20. The hyponotum is finely 

 wrinkled, the hyponotal line distinct. Colour usually uniformly black. 

 the marginal pores' white, but sometimes the whole of the back is 



