1! 



from the evolutionary standpoint of the Pteropoda alone, the 

 Australian " Eocene," as exemplified by the Lower beds of Muddy 

 Creek, Schnapper Point, etc., is younger than the Eocene of 

 typical districts like the London, Hampshire, and Paris basins. 

 A very common genus, for instance, in the Australian beds 

 mentioned is Vaginella, which, as will be seen hereafter, has 

 a distinct Miocene facies, and it is found in typical beds of 

 that age in Europe and America. Stijliola, again (when rightly 

 interpreted), is rather a Miocene than an Eocene subgenus ; as for 

 Spirialis, its range in time, from the Middle Eocene to the present 

 duy, imparts no evidence of homotaxial value. 



It will be observed that Styliola is here included as a subgenus 

 of Clio ; neither its embryonic nor its structural differences entitle 

 it to rank as a genus. Its structural features go to show that 

 Styliola is much more nearly related to Clio (^sensu stricto) than to 

 Creseis ; the forms included under the latter designation have 

 retained some of the more archaic characters of the LiMACiNiDiE. 



Genus LIMACINA, Lamarck. 

 [Anim. sans Vert. t. vi. pars 1, 1819, p. 291.] 



Seterofusus, Fleming, Mem. "Wernerian Soc. Edin. vol. iv. 1822, 



p. 498. 

 8piratella, Blainville, Diet. Sci. Nat. t. xxxii. 1824, p. 284. 

 Heliconoides, D'Orbigny, Voy. Amerique Meridionale, t. v. 1836, 



p. 174. 

 Spirialis, Eydoux and Souleyet, Eevue Zoologique, t. iii. 1840, 



p. 235. 

 Helicophora, Gray, Synopsis of the Contents of the Brit. Mus. 1842, 



p. 59. 

 Sca:a, Philippi, Fauna Moll. Sicilias, 1844, p. 164. 

 Protomedea, G. 0. Costa, Microdoride Mediterranea, 1861, p. 73. 

 JEmholus, Jeffreys, British Conchology, vol. v. 1869, p. 114. 



" Shell umbilicate, with turns gradually increasing ; with a 

 fairly large aperture ; and with a columella not prolonged into 

 a rostrum ; surface smooth or striated. The height of the spire, 

 the form of the surface and that of the aperture, and the size 

 of the umbilicus, vary according to the species." — Pelseneer. 



Limacina is universally regarded as a genus established by 



