1873.] MR. R. B. WATSON ON MADEIRAN MOLLUSKS. 363 



what oblique, descending towards the mouth-corner from the whole 

 last quarter of the body-whorl. 



Mouth bluish white, with a narrow dirty yellowish edge. In 

 form small, deep, very slightly patulous : in the depth of the throat 

 perfectly oval, but towards the outside angulated ; this angulation is 

 at the upper corner slight, but at the shoulder of the whorl more 

 distinct. The mouth thus resembles an irregular bowl of a spoon, 

 of which the canal forms the shank. Exclusive of the canal, it is 

 rather more than one third of the shell's length (i. e. as 8 to 22). 



Canal long, narrow, deep, and slightly excavated in under the left 

 side ; but its lips are not at all contracted. In its course it is 

 scarcely curved ; but in its general direction it bends a little to the 

 left. It ends in a semicircular notch. It is not at all recurved. 



Outer lip angulated, sharp, narrow, but strong ; internally quite 

 smooth ; not at all reflected, but a little patulous. It leaves the 

 body in a very straight, but slightly retreating line ; where it meets 

 the line of the first spiral ridge it turns angularly downwards with a 

 very slight curving in towards the line of the shell's axis ; just 

 below the lowest ridge it again alters (slightly) its direction, so as to 

 run more longitudinally and straight along the side of the canal : 

 just at the extreme point it swells a very little outwards. 



Inner lip quite smooth, expanded as a thickish glaze on the belly ; 

 it sweeps round there with a perfect oval curve. At exactly half its 

 length it is deserted by the great fold of the base which encircles 

 the umbilicus : from this point it still for ^ inch pursues the same 

 direction to the beginning of the canal ; there it turns sharply, and 

 throughout the rest of its course runs in slightly towards the axis of 

 the shell, overhanging the canal. Its edge all aloug the umbilicus 

 is very sharp. 



Pillar broad above, below cut off diagonally so as to expose to the 

 fullest the enormous circular umbilicus, which is almost as large as 

 the mouth, and which extends up into the heart of the shell ; it is 

 lined throughout with the epidermis ; within, it can be seen coiling 

 spirally upwards, the thick margin slightly marked by the old ends 

 of the canal. 



Operculum thick, horny, black, and claw-like ; nucleus at the 

 lower point ; surface scored from side to side with numerous slight 

 concentric lines. Its interior side is polished, with many slight 

 concentric lines on its inner margin and on its central flat, and with 

 a broad, thick, rounded border extending from its apex along its 

 outer margin. It is perfectly represented in all respects by the 

 picture in Adams's ' Genera,' pi. xvi. fig. 4, a, b, except that, as 

 seems generally the case in that work, it is turned upside down. 



Of this mollusk I have found (besides an unmistakable and 

 perfectly fresh fragment broken off by the dredge, in Funchal Bay) 



