results of the indefatigable labours of its author in a field then 

 little trodden and by few feet. The views expressed in it seem 

 to have undergone little modification since ; for though, appa- 

 rently rather in deference to the opinions of others than from 

 any conviction of his own, changes of opinion on some points 

 have been expressed by Dr. Mantell in later works, they are ex- 

 pressed without any grounds being stated whereon they were 

 adopted*. It can be no reflection on the Discoverer of the 

 Wealden and First Investigator of the Chalk to show that, amid 

 the multitude of objects which engaged his attention, one was 

 not followed out exhaustively. It is sufficient at present to say 

 that, whatever Dr. Mantell may have left undone in reference to 

 the Ventriculidae, has been hitherto filled up by no other hand. 



The different members of the large family of Zoophytes have 

 done so much towards the actual formation of the solid crust of 

 the earth, that anything which relates to any branch of it must 

 be interesting and important ; and it is certainly remarkable that, 

 amid the great attention given within recent years by so many 

 eminent observers to this family, no one has entered on an in- 

 vestigation of the Ventriculidae And yet the wide development 

 of these forms and their great elegance and variety cannot but 

 have attracted the attention of all who have ever glanced at the 

 contents of any good and extensive series of chalk fossils ; an 

 elegance and variety which the most untutored eye cannot fail 

 to notice and admire. 



I doubt not that the difficulty of the investigation affords the 

 real explanation of the neglect to which these bodies have been 

 subject. To investigate the living structure and affinities of an 

 entirely soft-bodied animal whose only remains have come down 

 to us encased either in intractable flint or in friable chalk will be 

 at once felt to be a task of no ordinary difficulty. Such a task 

 is very different from the examination of any living forms, to 

 whatever class they may belong, or even from that of any of the 

 more solid fossil forms, which latter themselves however call into 

 activity the greatest patience and skill of the ablest observers. 



Space will not permit me to examine in detail all the notices 

 which have incidentally been taken of different forms of the 

 Ventriculidse. I must confine myself to a brief glance at the 

 different works in which any direct allusion to these bodies may 

 be found, leaving it to the full details hereafter to be given of 



* 1 allude particularly to the separation of " Ocellaria " in the ' Medals 

 of Creation,' p. 279; to the stating Ventriculites to be a composite instead 

 of single animal in note to p. 272 of the same work; and to the still more 

 remarkable entire separation of " V. quadrangular is " (p. 283 ib>) and 

 placing it among Flustrte. 



