496 MAZATLAN UNIVALVES 
624, Nassa TEGULA, Pve. 
Conch. Ic. pl. 15, sp. 98. 
Comp. Buccinum tiarula,* Kien. Icon. Conch. p. 111, pl. 30. 
f. 4.— Rve. Conch. Ic. sp. 92.=(Nassa) Phrontis t. Z. fA. 
Ad. Gen. 1. 118. 
This shell looks like a very small N. luteostoma, with a white 
hp. It is of a prevailing slate colour, with a light band round 
the periphery, and a darker tint above. Sometimes the whole 
takes an olivaceous tinge. The labrum is more or less strongly 
lirate internally. The spiral strie are distant, and generally 
very faint ; but sometimes they are strong enough to make the 
ribs subnedulous. The last two ribs behind the varix degener- 
ate into tubercles. The operculum is the exact anologue of 
that of N. luteostoma, both normally, and in its frequent 
abnormal changes. The smallest of the adult specimens 
measures long. °42, long. spir.°17, lat. °27, div. 60°. 
Anacuminated sp. ,, ‘6, a A SS OOS ae ee 
A broad sp. aban s Pa . a etek neat! IPA aera 5 bv 
Hab.—Mazatlan ; not common; L’pool Col. 
Tablet 2384 contains 7 sp., in different stages of growth.— 
2385, 7 sp. adult, normal.—2386, 2 do. broad.—2387, 2 do. 
acuminated.—2388, 5 do. small variety (two with opercula in 
situ.)—2389, 6 sp. with opercula in situ, normal and abnormal ; 
two of the latter are very small in proportion.—2390, 1 normal 
and 2 abnormal opercula; sides of the jlatter with one or two 
prongs.—2391, 2 sp. mended after fracture.—2392, 5 sp. shew- 
ing development of spiral striz, nearly smooth to nodulous. 
624, b. Nassa PTEGULA, var. NODULIFERA, Phil. 
Nassa nodulifera, Phil. in Mus. Cum.:=(Nassa) Phontis n. 
H. &§& A. Ad. Gen. i. 118.—[Non N. nodifera, Pow. in Proc. 
Zool. Soc. 1835, p. 95. Galapagos and Panama, Cuming. 
=(Nassa) Uzitan. H. & A. Ad. Gen. i. 120.] 
NV. t. “NN. tegule” simillima ; sed costis ultimis haud obsole- 
tis ; striis spiralibus intensioribus ; colore supra fascia pallido, 
vubro-fusco maculato. 
The shells in the last tablet approach this so closely that it 
is more than probable that the species are identical; never- 
* The specimens in the B. M. Col. marked B. tiarula, Kien. were received from 
Mr. Powis as from ‘* South Seas’ and “‘Africa.”’ The habitat assigned by Reeve 
(without authority) to B. tiarula, is Madagascar. The two species are regarded by 
Dr, Baird as identical: they are here kept provisionally separate. 
