IIG CALIFORNIA ACADEMY OF SCIENCES. 



37. Lima (Mantellum) dehiscens Conrad. 



Lima de/itscens Con., ]our. Phil. Acad. Sci., Vol. VII, 1837, p. 247, PL XIX, figf. 7. Cooper, 7th 



Ann. Rept. Cal. St. Min., 1888, p. 245. Dall, Trans. Wagner Inst. Sci., Vol. Ill, Part4, 



1898, p. 769. 

 Lima orieiiialis (not of Ad. & RvE.) of Carpenter, Brit. Assn. Rept., 1863, p. 645. Keep, West 



Coast Shells, p. 168, fig. 142, 1892. Williamson, Proc. U. S. Nat. Mus., Vol. XV, 



1892, p. 193. 



Shell equivalve, compressed, obliquely oval, thin, white; anterior side straight; posterior 

 rounded ; umbones eared, posterior ears acutely pointed ; surface smooth, radiately striate with fine 

 grooves; hinge-area long, narrow, triangular; cartilage pit central, prominent; margin finely 

 crenulated. 



Ditnensions. — Long. 13 mm. ; alt. 18.5 mm. ; diam. 8 mm. 



Looks like an obliquely deformed Pecten. Specimen identified by Dr. Dall. 

 Rare in lower San Pedro series of Deadman Island; one specimen collected 

 by Mi-s. Oldroyd. 



Living. — Monterey to San Diego (Cooper): Santa Catalina Island (Arnold). 

 Pleido'cene. — San Pedro (Mrs. Oldroyd). 

 Pliocene. — Santa Barbara (Cooper). 



Superfamily ANOMIACEA. 



Family XL ANOMIID.E. 



Genus Pododesmus Philippi. 



Shell suborbicular, very variable, translucent and slightly pearly within ; attached by a plug 

 passing through a hole or notch in the right valve ; a single conspicuous byssal scar on the disk ; 

 valves radiately grooved ; hinge unarmed. 



Pododesmus rudis Brod. is a characteristic species. 



Section Monia Gray. 

 Adult hole or foramen large. 



Pododesmus macliroscTiisma Deshayes is a characteristic species. 



38. Pododesmus (Monia) macroschisma Deshayes. 



Anomia macrosc/iisma Desh., Reeve, Zool. Soc. Cuvierienne, 1S39, p. 359. Mag. Zool., 1841, PI. 

 XXXIV. MiDDENDORF, Beitr. Mai. Ross,, Bd. Ill, 1849, p. 6. Philippi, Abbild. 

 beschr. Conch., 1850, p. 132, PL I, fig. 4. 



Placunanomia viacroschisma Desh., Gray, Proc. Zool. Soc, 1849, p. 121. Cat. Anam. Brit. Mus., 

 1850, p. 12. Carpenter, Brit. Assn. Rept., 1863, p, 646. Tryon, Syst. Conch., 

 Vol. Ill, p. 294, PL CXXXI, fig. 76, 1884. Cooper, 7th Ann. Repi. Cal. St. Min., 

 1888, p. 260. Keep, West Coast Shells, 1892, p. 163, fig. 137. 



Placunajiomia {Monia) macroschisma Desh., Williamson, Proc. U. S. Nat. Mus., Vol. XV, 1892, 



P- 194- , 

 Pododesmus {Monia^ mactoscliisma Desh. ^Placunanomia ccpio Gray ^= Placitnanomia alope 

 Gray, {fide Dall, Trans. Wagner Inst. Sci., Vol. Ill, Part 4, 1898, p. 780). 



