MAZATLAN UNIVALVES 525 
Desh. in Lam. An. s. Vert. vol. ix. p. 610, no. 80.—C. B. Ad. 
Pan. Shells, p. 124, no. 141. 
Phylonotus regius, Swains. Exot. Conch. pl. 5, f. 15. 
Murex tricolor, Val. in Humb. Rec. Obs. vol. u. p. 300. 
Shell with 6-8 double varices uniting near the suture, where 
the posterior canal and two spines are open; about 10 others 
he behing the labrum, still open, the upper one on the siphonal 
canal crossing the others. ‘These are longer and narrower 
than in M. bicolor. Labrum deeply channeled to correspond. 
No false varix between the others. Labium expanded, not 
much raised. Siphonal canal scarcely bent, almost covered, 
leaving a small umbilicus. Mouth pinkish red, spotted with 
black on the edges. Surface covered with subgranular spiral 
lines. About 300 specimens sent in the L’pool Col. were acidu- 
lated and sold off: the specimens here inserted are from the 
S. W. Mexican collection. Long. 4°6, long. spir.1*, lat. 3°5, 
div. 100°. , 
Hab.—Acapuleo, Humboldt & Bonpland.—Panama; on mud 
banks at low water, (teste Rve.) Cuming.— Panama; in 
crevices of rocks between low water marks of spring and 
neap tides, common‘and fine, (5°3 by 4°2 in.) ; C. B. Adams.— 
S. W. Mexico, P. P. C.— Mazatlan; not uncommon ; 
L’pool & Havre Coll. 
Tablet 2504 contains 2 sp. not cleaned. , . 
671. PHyLLoNoTUsS PRINCEPS, Brod. 
Murex princeps, Brod. in Proc. Zool. Soc. 1832, p. 175.—Sow. 
Conch. Ill. no. 83, p. 43.—Kien. Icon. Conch. p. 56, no. 40, 
pl. 29; f. 1.—Desh. in Lam. An. 's. Vert... volo ixe ps eles 
no. 79.—Rve. Conch. Ic. pl. 6, f. 23, pl. 36, f. 24. 
Shell with about 7 varices, each with 3 pinnate fronds, and 
smaller palmule, open from the labrum, which is channeled 
and armed with white teeth within. On the siphonal canal 
(which is broad, scarcely bent, and almost closed) are two 
fronds, of which one crosses the lower labial frond. Labium 
short, and, with the mouth, white with a narrow brown rim. 
Columella scarcely bent. Posterior canal short, not foliated, 
marked off by a parietal tooth. The Mazatlan specimens are 
much more elevated than those figured by Sow. Kien. and Rve. 
It is presumed that this creature is very sluggish in its habits, 
as the whole shell, as far as the penultimate varix, is usually 
thickly inerusted with coralline, coral, Vermetidex, &c. Oper- 
