THE FORAMINIFERA. 57 



Balkwill and Wright describe and figure it in their admirable 

 list of Dublin Foraminifera. Their two specimens were 

 obtained respectively from ofi" the Hen and Chickens, Isle 

 of Man, and between the Isle of Man and the Mourne 

 mountains. 



Marginulina spp., d'Orb. 



Both ikf. costata and M. glabra are very rare. Of the 

 latter I have several very fair examples, but only one of the 

 former, and that has its terminal chamber broken. 



Vagimdina legumen, d'Orb. 



V. legumen is the only species of the genus I have seen, 

 and of this only a single example. 



Cristellaria spp., Lamk. 



C. crepidula is by far the most common of the three 

 species obtained in the district. A very fine example of this 

 species (now in the cabinet of my friend, Mr. W. Shone, 

 F.G.S.), was found by his mother, who was a most inde- 

 fatigable student of Foraminifera, in material obtained at 

 Hilbre Island. Several of the later chambers of the specimen 

 contain young Cristellaria, Most of these consist only of the 

 small globular shell which forms the primary chamber in the 

 genus, but several others have also added a second chamber 

 upon the first. The size of these young forms is such that 

 they could only be liberated upon the breaking up of the 

 parent shell. Mr. Brady has figured this peculiar specimen 

 on pi. Ixvii of his " Challenger " Foraminifera, in which 

 work may also be found numerous other examples of a 

 similar viviparous method of reproduction. 



Polymorphina spp., d'Orb. 



P. lactea, P, gihba, and P. communis are generally 

 present in all gatherings. P. thouini is a very rare form. 

 P. spinosa is exceedingly rare; previous to its discovery in 



