372 THE VOYAGE OF H.M.S. CHALLENGER. 



form a blunt, smooth, small top, with the extreme tip somewhat immersed ; these whorls 

 are very finely, but not quite regularly, microscopically spirally scratched. Whorls nearly 

 9, rather short, with a drooping shoulder and a blunt carination, from which they contract 

 with a scarcely convex profile to the lower suture ; the base is conical, very lop-sided, 

 scarcely convex, and prolonged into a very short snout. Suture sharp and well defined 

 by the swelling of the whorl above, and by the row of tubercles round the top of the 

 whorl below. Month oblong, a little oblique, pointed above, prolonged inta a shortish 

 oblique canal below. Outer lip well arched, with a very slight and open sinus above. 

 Inner lip — a very thin glaze runs across the concave line of the body and down the pillar, 

 which is obliquely cut off in front and has a twisted and sbghtly patulous inner edge. 

 H. 0-65 in. B. 0-21. Penultimate whorl, height O'll. Mouth, height 0-25, breadth O'l. 



In general form this species is slightly like a large Pleurotoma cerinum, Stimp. and Kurtz, but 

 is obviously quite distinct. It is a good deal like Ciionella tholoides, Wats., but is more scalar, is 

 smaller in the apex, longer in the base, and different in sculpture. 



3. Ciionella tholoides, 1 "Watson (PI. XXIV. fig. 1). 



Pleurotoma (Drillia) tholoides, Watson, Prelim. Keport, pfc. 11, Journ. Linn. Soc. Lond., vol. xvi. 



p. 248. 



Station 122. September 10, 1873. Lat. 9° 5' S., long. 34° 50' W. Off Pernambuco. 

 350 fathoms. Eed mud. 



Shell. — High, narrow, conical, ribbed, strong, with a rather short conical base, a very 

 blunt dome-shaped apex, and having the texture and colour of flint. Sculpture : Longi- 

 tudinals — there are on each whorl about 17 not very distinct, narrow, slightly swollen 

 ribs, which are a little convex backwards ; they run from suture to suture, but die out on 

 the base, and toward the mouth they become a little crowded and indefinite ; besides 

 these there are a great many fine, regular, hair-bke lines of growth. Spirals — there is on 

 each whorl, above the middle, an angulated carination, bearing a thread on its top, which 

 rises into rounded low tubercles where it crosses the ribs ; below this, a little below the 

 middle, is another thread, finer, less prominent, and with feebler tubercles, which also 

 marks a slight keel ; three other threads of about the same strength as this last, and at 

 very nearly equal distances, appear on the base : there are faint indications of others 

 besides, as also of microscopic scratches. Colour like pale flint in thin flakes ; but the 

 apex is white. Spire high, narrow, conical. Apex consists of 2^ embryonic whorls, 

 which form a blunt, smooth, round dome, with the extreme tip immersed but not hid. 

 Whorls 9 to 10, pretty high, angulated, a little constricted and concave above the keel, 

 and very slightly convex below it ; the base is conical, very slightly concave, and prolonged 

 into a short, slightly reverted snout. Suture sharp, and slightly canaliculated in con- 



1 6oKauir,i, dome-shaped, see the apex. 



