igi Costa Rico Miocene— Oi.sson 19 



cene time and have been noted by several writers. They 

 comprise the following species from Panama and Costa Rica, 

 listed together with the Pacific analogues: 



Panama or Costa Rica Pacific Analogue 



Area Patricia Sowerby Area grandis Sowerby 



Area {Noetia) MaeDonaldi Dall Area reversa Sovv^erby 



Ostrea niegodon Hanley 

 Maetra exoleta Gray 



Maetra estrellana Olsson Maetra {Harvetta) e leg an s ?:>ov:&T:hy 



Seinele laevis Sowerby var. 



costaiHcensis Olsson Semele laevis Sowerby 



Maeonia panainensis Dall variety 



eanalis OXsson... Maeonia panainensis Dall 



iWaeofna gatunensis Toula Maeoiria elongata Hanley 



Tellina erystallina Chemnitz also West Indian 



Antigona inultieostata Sowerby 



Antigona rugosa Gmelin also West Indian 



Pitaria eireinata Born variety 



altcrnata Broderip 

 Cyelinella subquadrata Hanley variety 



quitana Olfson Cyelinella subquadrata Hanley 



Cyelinella beteyensis Olsson Cyelinella A'royeri PhUi-ppi 



Conus reeognitus Guppy Conns pyriforniis Reeve 



Turricula lavinoides Olsson Turricula lavina Dall 



Caneellaria islaeolonis Maury Caneellaria tesselata Sowerby 



Cancellaria toroensis Olsson Coneellaria titbereulosa Sowerby 



Caneellaria Pluinmeri Olsson Cancellaria bullata Sowerby 



Mitra Swainsoni Brod. variety 



linionensis Olsson Mitra Swainsoni Broderip 



Neverita nereidis Maury Neverita glauca Humbolt 



Northia northiae Gray variety 



viioeeniea Olsson Northia narthiae Gray 



Malea eaniura Guppy Blalea ringens Swainson 



Oliva testacea Lam. variety 



eostaricensis Olsson Oliva testaeea L,am 



With the closing of the Miocene straits, this Pacific element 

 gradually had to give way before the development of the West 

 Indian fauna, but it is still to be seen in such species as, Tellina 

 erystallina Chem. Architectonica granulata Lamarck, which 

 have a distribution along both coasts. Moreover the Pliocene 



