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 lirulae. 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, Japan . 



Z. reticutata A. AD., Thes. Conch, iii, p. 209, f. 1, 2. Sows, 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 fins. 



Z. calceolina AD. Ann. Mag. K H. 1860, p. 302. AD. & SOWB. 

 Thes., p. 209, f. 3. SOWB., 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 thread lets 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 



