MARGARITA. 303 



lire is still very obviously different, and the form is globose, not, as 

 in that species, high and conical. ( Watson.) 



North of Culebra Id., W. Indies, 390 fms. 



Tr. (Margarita') pompholugotus Watson, Journ. Linn. Soc. xiv, 

 p. 702 ; Challenger Gasterop., p. 79, t. 5, f 9. 



M. iLLOTus Watson. PL 64, figs. 63, 64. 



Shell conical, with a tumid base, a scalar spire, and an impressed 

 suture, uncarinated, umbilicated, sharply spiralled, thin, brilliantly 

 nacreous, but with a squalid and dirty surface. Sculpture : Longitu- 

 dinals — there are dense lines of growth and remote puckerings of the 

 surface which might be called bars if they were continuous, but 

 except within the umbilicus they are not uniformly so; they follow 

 the lines of growth, and are thus very oblique ; they are stronger 

 above than below the periphery. Spirals — much more marked than 

 the longitudinals are the equal and regularly parted sharp spiral 

 threads which score the whole surface. Of these there are two or three 

 on the earlier whorls and four on all the later ; where they are 

 crossed by the longitudinal puckerings, they rise into small delicate 

 round white tubercles, which are sparse on the subsutural, and denser 

 on the peripheral threads; the four spiral threads on the base are 

 feebly dotted, but the two which lie near the umbilicus are somewhat 

 more strongly tubercled than any of the rest; there are none within 

 the umbilicus. Color white ; a thin calcareous layer covers the 

 brillant nacre of the shell but is obscured by a dirty deposit which 

 simulates an epidermis. Spire high and scalar. Apex broken. 

 Whorls 6} remaining, of rapid but regular increase, rounded, with 

 a short sloping shoulder above, and constricted below ; very tumid 

 on the base, suture distinct and impressed by the constriction of the 

 whorl above it. Mouth very perpendicular, roundly and gibbously 

 oval, bluntly angulated at the insertion of the outer lip, and at the 

 point of the pillar in front, dully nacreous within. Outer lip thin, 

 not descending, well arched. Pillar-lip with a direct edge, concave, 

 bending a good deal over the umbilicus ; it joins the basal lip at an 

 angle just where the spiral thread on the edge of the umbilicus occurs. 

 Umbilicus funnel-shaped and pervious, but a good deal contracted 

 by the convexity of the pillar ; internally it is scored by longitu- 

 dinal threadlets, and the strongly impressed suture coils around it 

 within. Alt. 0'62 in. diam. 0"57. Penultimate whorl height 0'14. 

 Mouth, height 0-31, breadth 0-26. ( Watson.) 



