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



a tendency to a backward curve of the lip-edge at that point ; and in this species there does not 

 exist the characteristic infra-sutural sinus which would connect it with Basilissa or with Seguenzia, 

 to which its tubercled pillar and closed umbilicus rather point. 



Margarita carinata, A. Ad., from the Philippines, has some points of resemblance with this, but 

 is obviously very different — markedly in the form of the umbilicus. 



19. Trockus (Ziziphinus) transenna, 1 Watson (PI. VI. fig. 3). 



Trochus (Ziziphinus) transenna, "Watson, Prelim. Report, pt. 4, Journ. Linn. Soc. Lond., vol. xiv. 



p. 698. 



Station 201. October 26, 1874. Lat. 7° 3' N., long. 121° 48' E. Philippines. 82 

 fathoms. Stones and gravel. 



Shell.- — Small, conical, high, carinated, inflated on the base, thin, sculptured, yellowish 

 with small ruddy spots. Sculpture : Spirals — close to the suture is a row of disconnected 

 beads ; between this and the carina are three rows of appressed beads, of which the 

 highest is the weakest ; these four rows are parted from one another by furrows, each 

 of which is a little broader than the thread above it ; the carina also consists of a row 

 of appressed beads ; it is stronger than the other threads both in breadth and height, and 

 the furrow above it is a little broader and deeper than the rest. On the base are seven 

 rows of appressed beads of nearly equal width and distance from one another; the first 

 joins the outer lip, the central row twines up the pillar. These rows of beads make 

 their appearance on the second whorl, and, on all the upper whorls, more than on the 

 body-whorl, the carina is sharply expressed by a constriction above and below it. 

 Longitudinals — the whole surface is crossed obliquely by not quite contiguous threads, 

 which are almost as strong as the spirals. Between the threads are narrow, deep, long 

 pits; each alternate thread is crowned by a bead at the suture. Colour: The surface is 

 dull and rough, yellowish, sparsely spotted on the spirals with a ruddy brown, which is 

 almost crimson on the infra-sutural beads. Spire high and conical, the whorls being 

 barely rounded. Apex small but flattened, the embryonic 1^ whorl scarcely projecting. 

 Whorls 7, of regular increase, almost flat, the body-whorl aloue being slightly convex, 

 rounded, and carinated at the periphery and tumid on the base, in the centre of which is 

 a most minute umbilical chink. Suture deeply and squarely impressed below the carina. 

 Mouth slightly oblique, squarish, nacreous. Outer Up very thin, very slightly descending, 

 and drawn in a little horizontally at its junction with the body, and then well rounded in 

 its whole sweep to the point of the pillar-lip, near which it is externally crenulated by the 

 ends of the basal threads. Pillar is short, straight, slightly tubercled on its inner side, 

 hardly toothed in front, and still less angulated at its junction with the outer lip. The 



1 A lattice. 



