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



They vary somewhat in the relation of length and breadth, and still more in the form of the crown, 

 which is sometimes flat and broadish, with an impressed sntnre, at other times narrow, with a small 

 deep opening and a very depressed apex, the suture in these circumstances being out of sight. I 

 should expect to find this species among Mediterranean shells, but have not been able to identify it. 

 It is not unlike Utriculus mamillatus (Phil.), but is stumpier and not so cylindrical, being broader 

 in front and more tapering backwards ; its papillary apex, too, is much smaller and more sunken into 

 the crown of the shell than it is in that species : the whole crown is very much like that of Utriculus 

 truncatulus (Brag.), but the characteristic constriction and sculpture of that species are wanting. < 



8. Utriculus amphizostus, 1 Watson (PI. XLVIII. fig. 11). 



Utriculus amphizostus, Watson, Prelim. Report, pt. 20, Journ. Linn. Soc. Lond., vol. xvii. p. 336. 



September 8, 1874. Flinders Passage, Cape York, North Australia. 7 fathoms. 



Station 186. September 8, 1874. Lat. 10° 30' S., long. 142° 18' E. Wednesday 

 Island, Cape York. 8 fathoms. Coral mud. 



Station 187. September 9, 1874. Lat. 10° 36' S., long. 141 c 55' E. Near Cape 

 York. 6 fathoms. Coral mud. 



Shell. — Small, rather broadly cylindrical, but contracted in the middle, and broadest 

 below the contraction, very bluntly rounded in front, longitudinally striate and very finely 

 spiralled, with a flat but slightly depressed crown and a small papillary apex. Sculpture : 

 Longitudinals — there are a great many small hair-like ridges and furrows on the lines of 

 growth; they are nowhere strong, but are feeblest on the base. Spirals — the whole 

 surface is very equally striated, with delicate shallow scratched lines parted by fiat surfaces 

 four or five times the width of the lines ; there is a very slight and gradual constriction, 

 most apparent near the outer lip about the middle of the body, and in front of this the 

 shell is slightly tumid. Colour translucent white, with vague trace of spiral bands. 

 Mouth the full length of the shell ; shaped like a racket, being oval in front, long and 

 narrow above ; it is small and rounded at the top, which just rises to the crown. Whorls 

 4, of which only the small rounded tops are seen on the crown, where they are slightly 

 and radiatingly ridged, the last envelops all the others. Suture impressed and distinct. 

 Outer lip rounded at the top, where it does not rise above the crown ; it runs straight 

 and parallel to the inner lip till below the middle, where it bends outwards in exact 

 symmetry with the corresponding bend of the inner lip on the base, forming a very 

 regular oval curve in front ; the edge line is regularly curved, retreating slightly behind 

 and in front, and advancing in the middle where the lip is contracted, lop flat, but 

 slightly depressed, with a small papillary apex in the middle, the outer edge is roundly 

 angulated. Inner lip straight down the body, concave on the pillar, which has a very 

 slight twist and a narrow patulous edge, behind which is a scarcely appreciable umbilical 

 depression ; the point of the pillar projects in front clear of the sweep of the basal curve. 

 H. 0*12 in. B. - 06. Breadth of mouth at same place, 0*02. 



1 a/i^/^woros, girt in. 



