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



front to become straight ; at the lower outer corner it is angulated, and across the base is 

 abruptly truncate. Inner lip has a very thin glaze, it is flatly convex on the body, 

 straight and elongately oblique on the pillar, which presents no tooth, but has a thin, 

 defined, hardly twisted edge, and is abruptly cut off in front, being there a strong pro- 

 minent point. H. - 083 in. B. 0-044. Mouth, breadth at same place, 0*007. 



This is very possibly a young shell. 



8. Cylichna crispula, Watson (PI. XLIX. fig. 12). 



Cylichna crispula, Watson, Prelim. Report, pt. 19, Journ. Linn. Soc. Lond., vol. xvii. p. 321. 



Station 185b. August 31, 1874. Lat. 11° 38' 15" S., long. 143° 59' 38" E. Raine 

 Island, Cape York, North Australia. 155 fathoms. Coral sand. 



Shell. — Narrowly oblong, more contracted above than below, with the greatest breadth 

 below the middle, obliquely truncate above and below, thin, translucent, glossy, very 

 faintly spirally striate all over ; the top is like that of a Volvula, but beside the prominent 

 lip the axis is perforated : there is a strong pillar tooth. Sculpture : Longitudinals — the 

 lines of growth are very slight and unequal. Spirals — the whole surface is covered with 

 very slight, superficial, fretted, rather unequal, and somewhat remote furrows. Colour 

 translucent glossy milk-white. Mouth long and narrow above, rising and retreating at 

 the top of the shell, widening in front, but not very large even there. Outer Up rises 

 from the edge of the axial pore, and forms the top of the shell ; at this point it is narrowly 

 rounded and retreats very much, below this its edge advances and its direction is obliquely 

 forward to the right ; in front it retreats rather rapidly and sweeps freely round the base 

 to the point of the pillar ; it is a little bent in about the middle, but is very patulous on 

 the base. Top is very small, and fully half of it is covered by the lip, but behind this 

 there is a minute conical depression with a defined rounded edge. Inner lip is regularly 

 arched on the body, where there is a thin glaze, which becomes thick on the pillar with a 

 twisted sharply-defined edge. Pillar bears a strong, almost direct tooth, with a well- 

 marked broad furrow between it and the lip edge. H. 0'16 in. B. 0"075. Mouth, breadth 

 at same place, 0"017. 



This species is deceptively like a Volvula. In general form it resembles Atys parallcla (Gould), 

 but is smaller, is more contracted above, and is there- minutely perforated ; the tooth in front, too, 

 is stronger, and the spiral sculpture is much finer. 



9. Cylichna noronyensis, Watson (PI. L. fig. 1). 



Cylichna noronyensis, "Watson, Prelim. Report, pt. 19, Journ. Linn. Soc. Lond., vol. xvii. p. 322. 



Station 113a. September 2, 1873. Lat. 3° 47' S., long. 32° 24' 30" W. Anchorage 

 off Fernando de Noronha. 7 to 25 fathoms. Volcanic sand and gravel. 



