74 THE VOYAGE OF H.M.S. CHALLENGES. 



of the whorls is not angulated. Than Trochus (Solarictta) prodictus, Fisch. (= angulatus, A. Ad.), 

 this Port Philip species is much larger and higher. It approaches most nearly to Trochus (Solaridla) 

 bcllula, Ang. ; but that is larger, with the same number of whorls, has a transparently white apes, has 

 the shoulder below the apex not flat nor drooping outwards, but gouged out as a concave depression ; 

 the last whorl is more spread out, and the base is without colour ; the umbilicus is wider and less 

 deep, and the spiral which defines it is stronger, while there are no other spirals within it ; the whole 

 surface of the shell, too, is smooth, with a few strong clean-cut impressed spirals, instead of being 

 closely and minutely fretted with spirals all over. 



39. Trochus (Solaridla) lamprus, Watson (PL VI., fig. 9). 



Trochus (Solaridla) lamprus, Watson, Prelim. Report, pt. 5, Journ. Linn. Soc. Lond., vol. sv. p. 93. \ 

 July 29, 1874. Levuka, Fiji. 12 fathoms. 



Shell. — Depressedly conoidal, angulated at the periphery, rounded on the base, umbili- 

 cated, polished, finely sculptured, solid. Sculpture : The glossy surface is closely fretted with 

 fine, curved, oblique, longitudinal scratches, crossed by very similar but slightly stronger 

 and more equal spirals ; these both are stronger near the suture and feebler on the base, 

 where, indeed, the spirals almost disappear. Colour pellucid pale yellowish white, with 

 many narrow, opaque, pure white spirals, which are flecked with fine zigzag brown longi- 

 tudinal lines, aggregated in spots, and most abundant near the suture. The strongest 

 opaque spiral is at the periphery, and on it are minute linear interruptions of the 

 fundamental colour, and very regularly recurring little brown spots, which are about half 

 the width of their interspaces. On the base the brown spots are very few and minute. 

 There is very little iridescence anywhere. Spire low. Apex minute and projecting. 

 Whorls 6, depressed, equally curved, slightly angulated at the periphery, more flattened 

 on the base than above, of regular, but rather rapid increase. Suture slightly impressed. 

 Mouth small, rounded. Outer lip thin and perfectly simple. Inner lip porcellanous, thick 

 and flat, projecting in a minute ear across the umbilicus, and having toward the point of 

 the pillar a broad backward bevel, cut out of the thickness of the shell round the umbilicus. 

 Umbilicus, a shallow open depression, with a deep narrow hole in the centre. H. - 15 in. 

 B. 0-24, least 0*2. Penultimate whorl, 0'05. Mouth, height 0-13, breadth O'l. 



The specimen from which this species is described is not quite full-grown. The whorls are not 

 angulated, nor the umbilicus open, nor is the colour ruddy, nor the texture thin, as in Trochus 

 (Solaridla) prodictus, Fisch. From Trochus (Solaridla) vitiligincus, Mke., from which it differs in 

 these respects, but in a less degree, it may further be distinguished by its greater depression, its 

 smaller mouth, its weaker sculpture, its greater glossiness, its feebler iridescence, and its minute 

 umbilicus. 



