GEOLOGICAL MEMOIRS. 



Trochus pygniaeus, Ph. fPyrula Santangeli, Mar. 



f carneolus, Lam. Murex tetrapterus, Bronn. 



Turbo neritoides, L. Tritonium variegatum, Lam. 



littoreus, L. scrobiculator, L. 



obtusatus, L. cutaceum, L. 



muricatus, L. Chenopus sirresianus, Mich. 



Scissurella plicata, Ph. Cassidaria depressa, Ph. 



striatula, Ph. Dolium galea, L. 



Ceritbium laevigatum, Ph. Buccinum Scacchianum, Ph. 

 Pleurotoma purpureum, Mont. candidissimum, Ph. 



costulatum, Riss. Tirei, Mas. 



multilineatum, Desh. Lefebvrii, Mas. 



pusillum, Scac. Terebra aciculata, Lam. 



plicatiim, Lam. Ovula carnea, L. 



taeniatum, Desh. fCjTpraea annulus, L. 



Bertrandi, Pay. f moneta, L. 



laevigatum, Ph. erosa, L. 



secalinum, Ph. helvola, L. 



Laviae, Ph. Dentalium rubescens, Desh. 

 Pyrula squamulata, Ph. 



Cirripeda. 



Balanus intermedius, Ph. Coronula bissexlobata, Blain. 



hemisphaericus, Brg. Anatifa laevis, Brg. 



galeatus, L. striata, Brg. 



Acasta spongites, Poli. Pollicipes scalpellum, L. 

 Chthalamus glaber, Poli. 



Since the tertiary period, therefore, there have been introduced 

 as new species — 



Of the 188 existing Conchifera 35 species, or 19 per cent. 



„ 10 „ Brachiopoda 4 „ 40 „ 



„ 11 „ Pteropoda 6 „ 58 „ 



„ 313 „ Conchiferous Gasteropoda 97 „ 31 „ 

 „ 15 „ Cirripeda 9 „ 60 „ 



On the other hand, the following 193, or nearly one-third of the 

 species found fossil, have disappeared and are now extinct : — 



Conchifera, 



Aspergillum maniculatum, Ph. Thracia elongata, Ph. 



Clavagella bacillaris, Desh. Tellina pusilla, Ph. 

 Clavagella sp. pleurosticta, Ph. 



Pholas vibonensis, Ph. ovata. Sow. 



Solen tenuis, Ph. elliptica, Broc. 



Solecurtus multistriatus, Scac. strigilata, Ph. 



Panopaea Faujasii, Men. Diplodonta lupinus, Broc. 



Bivonae, Ph. Lucina transversa, Bronn. 

 Anatina oblonga, Ph. albella, Lam. 



pusilla. Ph. Scacchia inversa. Ph. 



Scrobicularia tenuis. Ph. Astarte laevigata, v. MUnsi. 



Erycina pusilla, Ph. Cytherea fragilis, Ph. 



angulosa, Bronn. Venus senilis, Broc. 



longicallis, Scac. vetula, Bast. 



similis. Ph. ? miliaris. Ph. 



Corbula crispata, Scac. Cardium multicostatum, Broc. 



costellata, Desh. Hippagus acutecostatus, Ph. 



Thracia ventricosa, Ph. Area mytiloides, Broc. 



