ZEIDORA. 247 



"deck" like Crepidula. Surface cancellated ; front slope grooved 

 by a slit-fasciole having elevated edges. 



This little-known genus seems to stand between Puncturella and 

 Emarginula. 



Z. reticulata A. Adams. PI. 64, figs, between 16 and 20. 



Oblong, the back convex ; decussated with elevated radiating 

 lines and concentric lirulse. Margin crenulated ; fissure deep, nar- 

 row. This species differs from Z. calceolina in being more convex, 

 less obtuse anteriorly, and in the fissure being narrow and deeply 

 incised ; the sculpture moreover is very different, being finely retic- 

 ulated instead of widely cancellate. {Ad.) Length 4 mill. 



Mino-Sima, J<tj"m. 



Z. reticulata A. Ad., Thes. Conch, iii, p. 209, f. 1, 2. — Sown, in 

 Conch. Icon, xix, f. 1. 



Z. calceolina A. Adams. PI. 64, figs. 27. 



Oblong, elegantly cancellated with elevated radiating and con- 

 centric lines ; sides of the median furrow elevated ; apex posterior, 

 deflexed ; edge of the septum acute, entire. Wider and more de- 

 pressed than Z. reticulata, and the concentric and radiating lines 

 form a much wider net-work. (Ad.) Length 4 mill. 



Sts. of Corea, 16 miles from Mino-Sima, Japan, in 63 fms. 



Z. calceolina Ad. Ann. Mag. N. H. 1860, p. 302.— Ad. & Sown. 

 Thes., p. 209, f. 3.— Sows., Conch. Icon, xix, f. 2. 



Type of the genus Zeidora. 



Z. naufraga Watson. PL 27, figs. 55, 56, 57, 58. 



Shell white, delicate, depressed, oblong, pointed behind, with a 

 minute short apex, rounded and cleft in front, with a broad flat 

 keel bearing the old cleft-scar and extending the whole length of 

 the shell ; the enormous mouth is closed behind by a crepidula-like 

 partition. Sculpture : Longitudinals, from the apex to the cleft 

 across the middle of the back runs a broad raised keel, flat on the 

 top, where it is scored by the minute, delicate, sharp, prominent, 

 close-set, but not contiguous scars of the old cleft ; on either side it 

 is bordered by a sharp marginal line : from these marginal lines 

 branch off feeble irregular diverging threadlets between which, as 

 they go wider apart, others arise ; the intervals between them are 

 two to three times the breadth of the threadlets. Spirals, strictly 

 speaking, there are none, but the whole surface is scored at right 



