MAZATLAN UNIVALVES 455 



Triton nodosum, Mke. in Zeit.f. Mai. 1850, p. 189, no. 78. 



Murex argiis var. h. pars, Gmel. 3547, no. 78. 



Triton Chemnitzii, Gray in Zool. Beech. Voy. p- 110, (1839.) — 



Rve. Conch. Ic. pi. 11, f. 37.— C. B. Ad, Pan. Shells, p. 115, 



no. 126. 

 Fusus Wiegmanni, Anton, Verz. p. 77, (1839.)— PAiZ. Ahhild. 



pi. 2, f. 2, 4 var. 

 Lagena Wiegmanni, H. ^ A. Ad. Gen. i. 104. 

 Cassidaria setosa, Sinds, Piibi. 

 Triton perforatus, Conr. Proc. Ac. N. S. Phil. vol. iv. p. 156 



(Feb. 1849) -.—Journ. A. N. S. Ph., n. ser., vol. i. p. 280, 



pi. 39, f. 6 var. 



Shell ventricose ; very tkin or rather solid ; spire more or 

 less elevated ; shoulder either round, or (usually) with a more 

 or less developed roimded keel ; canal varying in length and 

 twist, shewing more or less of an umbilical chink ; colour 

 tawny, sometimes with the spiral ribs purplish brown. Mouth 

 and spire often seen without varix ; penultimate varix either 

 absent, or at variable distances from the last, which is not 

 prominent, sharply serrated by the projections of the internal 

 teeth which are generally grouped in pairs. Labium nearly 

 smooth, or with more or less prominent white corrugated teeth 

 on a purplish brown ground. Nuclear whirls smooth, turrited, 

 deciduous, fixed slanting on the rest, which are at first cancel- 

 lated, afterwards only with spiral costse, sometimes obsolete. 

 The epidermis is extremely thin and deciduous, crossed by 

 more or less frequent scaly rows, ending in bristly hairs. 

 The opercula were unfortunately not sent. The shells are 

 free from incrustations. The largest of the specimens mea- 

 sures long. 4 '66, long. spir. 1"66, lat.Z'O^, div. 70". 

 A small rounded sp. „ 3*12, „ 1-2, „ 2-18, „ 80". 

 A broad sp. „ 3*55, „ 1-2, „ 2*66, „ 80". 



Tablet 2064 contains 1 sp. rounded whirls. — 2065, 3 sp. nor- 

 mal state.— 2066, 3 do, colour developed.— 2067, 2 do. keel 

 developed. — 2068, 5 sp. shewing variation in varices ; the 

 ultimate and penultimate being distant 100", 140", 210", 250", 

 and 300" respectively. — 2069, 2 sp. one with penultimate varix 

 swoUen but not marked off; the other do. foliated. — 2070, 

 2 sp. one with spiral costa; broad and distant ; the other do. 

 nearly obsolete. — 2071, 1 sp. mended after fracture. — 2072, 1 sp. 

 after hot acid process, varix forming. 



