of the Chalk. 91 



rived from the base of the body " prolonged into a stirps and 

 attached to other bodies." The body of the Ventriculite tapers 

 off regularly to a point at the bottom. At about an inch from 

 its base, — the distance varies according to size, — fibres of a very 

 different aspect from those composing the membrane of the body 

 begin to be attached to the external part of that body. They do 

 not begin all round at exactly the same distance from the base, 

 nor, as they increase in mass, is that mass of the same thickness 

 on all sides. They are at first very few and thinly disposed. As 

 the base narrows they increase rapidly in number and mass, till, 

 immediately below the base, they form a bundle of considerable 

 size, which is continued, thus united, for some distance, from one 

 to three inches according to circumstances, when it divides into 

 several radicles, sometimes more, sometimes less : I have counted 

 as many as forty in one specimen. These sometimes extend very 

 far and always terminate in very delicate extremities. 



The root-mass is never itself convoluted like the body, even in 

 its upper parts, and where it forms a thin membrane only. It 

 necessarily follows the form of any convolution, usually slight, 

 which exists at the lower part of the body. The mass of the root 

 is not regularly cylindrical, but irregular on the different sides 

 (see PL VII. fig. 6). Occasionally it assumes a tubular aspect in 

 places, but this is quite accidental and in nowise characteristic 

 of genus or species. 



PL VII. fig. 5 gives a longitudinal section in which the differ- 

 ence between the body and root is very clearly seen : fig. 6 is a 

 transverse section of the same specimen. These two will realize 

 to the observer how admirably the body was lodged in this root- 

 case as in a sheath or socket. They remind one of a balloon to 

 which the car is attached by a network of rope gathered in on all 

 sides round the narrow base. PL VII. fig. 7 is the external appear- 

 ance of another specimen, showing the root-fibres commencing 

 round the body and spreading at the root. 



The substance of the root was different, as the fibres were dif- 

 ferently arranged from those of the body. This is proved by 

 the fact that the root exists generally in a very different condi- 

 tion, both in chalk and flint, to that in which the body is found 

 in the same specimen. In flint its place is much less often 

 solidly filled with calcedony than is that of the body. In the 

 chalk it is the rare exception to find the substance of the root in 

 sound condition. It generally falls away to dust the moment 

 the specimen is opened, while the body of the Ventriculite re- 

 mains entire and perfect down to its very point, having all around 

 it a hollow space where the root was. 



The Ventriculites were never " affixed to other bodies." It is 

 possible that the animal was locomotive like the Actinia, and that, 



