ON MOLLUSCA OF THE WEST COAST OF NORTH AMERICA. 557 
. Sp. 
2 8. Spiroglyphus albidus, ?Cpr. Mazatlan, Reigen. Operculum g et ?f, Maz. 
Cat. p. 311.=Bivonia albida, Cpr., Maz. Cat. p. 807. Opere. g is with- 
out doubt of Spiroglyphus, and not of Bivonia, var. indentata. Operc. f 
is truly congeneric, and perhaps conspecific. 
544 4. Vermetus (Thylacodus) contortus, Cpr.* Gulf Calif. Mus. Cum. 
vs oes Var. a. repens (Thylacodus). Gult Calif., on Margaritifera, Mus. Cum. 
“This species is perhaps a state of V. (Petaloconchus) macrophrag- 
ma.”  [Mérch: non Cpr. ]+ 
O40 | Var. B. favosa (Thylacodus). Calif., on Crucibulum. Mus. Cum. 
+s oes Var. y. eontortula (Thylacodus). Gulf of California. 
mes, Forma 1. ?Thylacodus contortus, var. indentata, Cpr.“ Corre- 
sponds to forma 1, electrina, of Vermetus varians, D’Orb.” 
+» oss Var. 6. endentata (Vermetus), [Morch, non Cpr.}. Sonsonate, on Spon- 
dylus limbatus, Rye., non Shy. Oersted. 
846 ., Var. «. corrodens (Vermetus). Is. Sibo (PQuibo), Spengler, on Pur- 
pura lineata. 
359 20. Vermetus (?? Strebloceras) anellum, Mirch. California, on Hallotis tuber- 
culatus, Rve. [Not a Californian Haliotis. The diagnosis, however, 
exactly accords with aCalifornian shell, which is perhaps the young of 
S. squamigerus. It has no resemblance to Strebloceras, Cpr., P. Z. 8, 
1858, p. 440, which is a genuine Cwcid. 
360 21. Vermetus (Macrophragma) macrophragma. Mazatlan, &c.= Petaloconchus 
m., Cpr. Realejo, Oersted. 
362 24. Vermetus (Aletes) centiquadrus, Val. Puntarenas, Oersted + V. effusus, 
Val. (the same specimen). 
Bei Var. a. maxima=V. Panamensis, Chen, pl.5, £1. Panama, C. B. Ad. ; 
Mazatlan, Melchers. 
var Var. B. Punctis impressis destituta,= V. Péronii, Val.t 
363. Var. y. siphonata. Puntarenas, Oersted= V. Péronii, Rouss. 
+» «+ Var. 6. tulipa. Gulf of California, on piece of black Pinna, Mus. Cum, 
[The Pinna nigrina is from the E. I.]=V. tuipa, Rouss. 
2a Be Var. «. Bridgesii. Panama, on Margaritifera, Mus, Cum. 
The conclusion of the paper is in P, Z. S, 1862, pp. 54-83. 
58 4, Bivonia sutilis, Mérch. Central America, on Anomalocardia subimbricata, 
Mus. Cum. 
«» 4+ Var. a. Pmajor. On Pinna, probably Central America, Mus. Dunker. 
-» 4s War. 8. triquetra, Mazatlan, on valve of Placunanomia, Mus. Semper. 
Like B. triquetra, “ var. typica.” 
70 8. Thylacodes cruciformis, Mirch. California, on Crucibulum Pumbrella, 
Desh., var. Mus. Cum. Analogue of 7, 7. Riisei, Mirch, from the 
east coast. 
ss ee Var. #. lumbricella. Voy. Ven. pl. 11. f 2. California, crowded on 
Margaritifera. Mus. Cum. 
+s «+ Var, 8. erythosclera. Cal., on young Margaritifera. Mus. Cum. 
Very like Biv. Quoyt, var. variegata. [This species is on shells from 
the Mexican, not the “Californian ” Bee 
76 16. Thylacodes squamigera, Cpr.,= Aletes sg., Cpr., P.Z.S. 1856, p. 226. Sta. 
Barbara, Nutt. | Serpulorbis, not Aletes, teste Cooper. 
* Mr. Mérch has not seen any laminz inside, but, from the 3-5 spiral lire on the 
columella, believes they will be found. The opercula supposed to belong to this species 
(Maz. Cat. p. 311) Mr. M. thinks more probably those of Spiroglyphus albidus. He 
states (erroneously) that the shell was not opened by the describer. 
+ Morch supposes that Bivonia contorta, Cpr., may be the adult of Petaloconchus 
macrophragma, and that both may be forms of Aletes centiquadrus. The nuclear por- 
tions are, however, quite distinct, and the three shells appear, from beginning to end, as 
far removed as any ordinary Vermetids can be from each other. 
{ The writer doubts respecting this species, and thinks the shell on which it is para- 
sitical to be a Melo, and not Strombus galea, simply because named after Péron, who 
did not visit this district. 
