19 



Description. 



1 have derived the specific name ROTUNDVS, from the animal having a round 

 column. 







The remains of the APIOCRINITES ROTUNDUS have as yet only occurred in a 

 fossil state, and no perfect specimen has been met with. At Bradford the al- 

 most shapeless bases (PL. ii. fig. Land 9.) of this species are met with, adhering 

 to the surface of the oolitic rock, of various sizes, inclosing portions of thecolumi> r 

 which are seen externally shooting forth from them. They are affixed in great 

 number to each other, and not unfrequently to testacea and other extraneous 

 marine bodies, which proves that the animal lived in the sea, and affixed itself 

 wherever chance directed its ovum. Portions of the column (PL. iv fig. 1.) the 

 animal's superior pear-shaped part (PL. i. fig. 2.) and the separate joints of 

 both are generally found in the clay which covers the oolite. As cellepores 

 shells and serpulte (PL. 11. fig. 9) adhere to them, they must have been of a 

 firm texture, and as these frequently occupy the inner surfaces of joints (PL. n. 

 fig. 1) the remains of these animals must have lain for some time in a dead and 

 separated state, before they were covered with the mass of the stratum in which 

 they are imbedded. The comparatively rare occurrence of portions of the 

 column, its short fragments, on which I never could trace the slightest mark 

 indicating side arms, and the bulky superior part, point out that the column at 

 no time could have been very long (PL. i. fig, 1.) since otherwise the animal 

 would have been continually in danger of mutilation from the over poising 

 weight of its superior part; and the more so as from its want of side arms it 

 could have possessed qo lateral support to counteract this weight. 



The COLUMN, as has been observed, is formed of numerous round depressed 

 joints (PL. iv. fig. 1 and 6) pierced in the centre to afford a passage to the 

 alimentary canal (PL. iv. fig. 20. PL. in. fig. 4.) Their upper and lower sur- 

 faces are striated in radii, of which the depressed spaces admit the elevated ones 

 of the next joint. The radii are at certain distances interrupted by concentric 

 of(more or less)elevated rings, parallel to the circumference of thecolumn, which 

 are more conspicuous towards its apex. (PL. IY. fig. 8, 9, and 14.) At each of 

 these interruptions the radii divide (forming sometimes minute tubercles) thus 

 increasing their number as the animal grows. This increase of the number o 



