236 HELIX-OBBA. 



obtusely toothed within, parietal wall covered by a thick deposit of 

 callous. Alt. 20, diam. maj. 24, min. 21 \ mill. 



Halong, Tonquin. 



H. merarcha MABILLE, Bull, de la Soc. Philomathique, Paris, 

 1888. 



A very distinct form. The dome-shaped spire, strong striation, 

 and callous fold within the outer lip are the more obvious characters. 

 My description and figures are drawn from the unique type in the 

 collection of L' abbe A. Vathelet, Ammonier de la Division navale de 

 1'Atlantique. 



Group of H. codonodes. 

 This group is equivalent to Janira of Albers. 



H. CODONODES Pfeiffer. PL 53, figs. 8, 9, (type) ; 10 (var.) 



Shell umbilicated, globose-conoid, solid, obliquely striatulate, very 

 subtly sculptured with close spiral lines ; white or straw-colored, 

 shining, with one or two chestnut bands ; spire bell-shaped, apex 

 obtuse ; whorls 5, scarcely convex the last descending in front, 

 base gibbous, then subconstricted behind the aperture; aperture 

 oblique, subquadrangularly rounded ; peristome thickened, reflexed, 

 the margins subapproximating, joined by a shining callus ; col- 

 umella having a tooth-like protuberance inside, dilated outwardly, 

 sinuous. Alt. 17, greater diam. 20, lesser 17 mill. (P/r.) 



Great Nicobar Island. 



H. codonodes PFR. P. Z. S. 184G, p. 112 ; Mon. i, p. 321 ; Conchyl. 

 Cab. p. 282, t. Ill, f. 15, 16, and var. minor, 1. 128, f. 3, 4. REEVE, 

 f. 91. Helicostyla (Janira*) codonodes MORCH, Journ. de Conchyl. 

 xx, 1872, p. 312 (with vars.). 



Var. minor e Morch. (pi. 53, fig. 10). No bands. 



Var. subcylindrica Morch. Larger, with sutural and median 

 black bands. Alt. 27, length of aperture 15 mill. 



Var. edentula Morch. Shell thin, having two very obsolete 

 bands ; alt. 28, length of aperture 11 mill. 



H. CAMPANULA Pfeiffer. PL 53, figs. 11, 12, 13. 



Shell umbilicate, globose, solid, subtly and regularly obliquely 

 striated ; chestnut colored ; spire semiglobose, apex obtuse, pale ; 

 whorls 4o, a little convex, the last scarcely wider than the preceding, 

 scarcely descending in front, having a pale girdle in the middle. 



