Foiinninifera. 135 



entiation of the animal is much more distinct, and from a study 

 of these, and kindred forms, we can judge somewhat of the 

 nature of the animal living in these calcareous and sandy tests. 

 Schultze, Schulze, Gruber and others have thrown much light 

 upon the biology of the Protozoa, and there have been recently 

 published by Miss Greenwood, of Cambridge, some interesting 

 and careful papers on " Digestive process in some Ehizopoda."* 



The simple nature of these organisms (Protozoa) makes us 

 despair of getting exact particulars as to their economy, but on 

 one point, and that perhaps the most important of all — the sex 

 and reproduction — we have, if not very definite information, at 

 least some very important details. Amoeba and Actinophrys are 

 believed to be asexual, and to reproduce themselves solely by 

 fission or gemmation. Amongst the Foraminifera it is extremely 

 likely that both these methods obtain ; and we have evidence of 

 a thu'd method, that of viviparous rej)roduction, and this may 

 possibly indicate sex. In 1854, Max Schultze published his 

 remarkable work, ' Der Organismus der Polythalamien,' and he 

 figured therein a MUiola and a liotalia, in both of which 

 numerous young shells are shown. Ehrenberg and Strethill 

 Wright also noticed this in SpinlUna. In 1883 Shacko pub- 

 lished in the ' Archiv der Naturgeschichte,' a paper in which he 

 describes and figures a PcneroiMs proteiis, d'Orb., showing the 

 last fourteen chambers of the shell crowded with embryos ; and 

 to be more exact he figures another specimen, to show that the 

 shape of the embryo corresponds exactly with the original 

 chamber of the parent shell. Again, in 1884> Brady figured in 

 the ' Challenger ' Eeport a specimen of CristcUana crepidida, in 

 which young shells are seen occupying some of the chambers. 

 As there is no orifice in these shells (with the exception of 

 Spirillina) sufficiently large to admit of the passage of the 

 young to the exterior, it seems highly probable that the birth of 

 the young means the death of the parent, unless indeed an 

 actual segmentation of the parent takes place to produce the 

 young. This, however, is merely suggestive ; but we have the 

 same thing taking place when Amoeba divides into two ; the 

 parent ends independent life, and becomes two immature indi- 

 viduals. In Ctjmbalopora, one of the RotalincB, the last or 

 youngest chamber of the mature shell is much inflated, and 

 young shells are found therein, and Mr. Brady has noticed the 

 presence of the rotaline portion of the shell, showing traces of 

 the fractured balloon-shaped chamber amongst mature and 

 young individuals. 



De la Harpe, when studying the Nummulites, observed that 

 there are two recognisable forms of each species, the individuals 



* ' Journal of Physiology,' 1886 and 1887. 



