428 MAZATLAN UNIVALVES 
of her most accurate and careful labourers. Long. *15, long. 
spr. °125, lat. °036, div. 11°. 
Hab.—Mazatlan ; 12 sp. off Chama & Spondylus ; L’pool Col. 
Tablet 1990 contains the finest specimen. 
520. CHEMNITzZIA Pstmtuis, C. B. Ad. 
Pan. Shells, no. 228, pp. 168, 312. 
There being no type of this species in Mr. Cuming’s collec- 
tion, it is determined with doubt. It is described as differing 
from Ch. Panamensis in being shorter, with the whirls rather 
more convex, and the periphery rounder.. The apex has 3 
turns, and projects beyond the margins of the spire. The 
largest specimen, which has nine whirls, and is beautifully 
translucent, measures Jong. ‘072, lat. ‘028, div. 20°. 
Hab.—Panama ; 2 sp. in the sand; C. B. Adams.—? Mazatlan ; 
6 young sp. off Chama and Spandylus; L’pool Col. 
» Tablet 1991 contains the finest specimen. 
521. CHEMNITZIA ACULEUS, @. B. Ad. 
Pan. Shells, no. 219, pp. 164, 311. 
Shell extremely slender, but with the upper whirls not 
nearly so pointed as in C. gracillima. The apex in Mr. Cum- 
ing’s type specimen has 3 turns and slightly projects beyond 
the line of the whirls. Tuese are scarcely convex, with 14—17 
stout ribs formed by the scooping out of smooth interstices 
which end on the periphery. The largest specimen, with ten 
whirls, measures long. °13, long. spir.*108, lat. °03, div. 12°. 
Hab.—Panama; 4 sp. in sand; C. B. Adams.— Mazatlan ; 
6 do. off Chama and Spondylus, dead; LZ’pool Col. 
Tablet 1992 contains the least worn of the specimens. 
522. CHEMNITZIA MURICATA, 2. s. 
Ch. ¢. satis gracili, alba, subdiaphand ; vertice nucleoso anfr. 
il., rotundatis, marginihus spire rectis vix superante, tumente ; 
anfr. normalibus vu. angustis, planatis, clathratis ; liris ectr- 
citer xvii. solidis, rectis, vix declivibus, plerumque lineis ad 
apicem decurrentibus ; suturd impressd ; liris ad suturam 
prominentibus, muricatis ; interstitiis usque ad peripheriam 
