41 



class Acicula, and to the genus Sudes villarwn, are formed of a substance 

 which has a spathose appearance, those belonging to the Sudes for talitio- 

 rum, or palisadoes, are composed of a porous substance, in consequence 

 of which they do not sink in water as those of every other genus do. 



Among the numerous riddles which the admirers of fossils have to 

 solve, there has been hardly any one more involved in puzzle than the 

 original nature of the belemnite. A considerable progress had, how- 

 ever, been made in removing the mystery, when fresh difficulties started, 

 in consequence of the peculiar appearances discovered in some fossils, 

 which were sent to Klein by his friend Fischer, from Studtgard. 



These bodies, although of a dark colour and striated from the centre to 

 the circumference, and generally considered to be belemnites, were, in 

 the opinion of Klein, the spines of echini. Descriptiones TubuL Mann. p. viii. 

 To this opinion he was led by their figure, their seeming spathose substance, 

 and by their striae concentering in a line passing longitudinally through the 

 centre of the body, in which no trace of a canal was observable. Led by 

 the examination of these bodies, which bore a resemblance so strong both 

 to belemnites and to the spines of echini, he formed these, as it will 

 appear, just conclusions : That all fossils, resembling belemnites in 

 their substance and figure, are not to be referred to belemnites ; that all 

 belemnites cannot be considered as spines of echini ; and that the sub- 

 stances naturally constituting the belemnite and the aculeated, if not all 

 the spines of the echinus, were such, as to be capable of under- 

 going the same kind of change. The fossil figured by Lhwydd, Li- 

 thoph. No. 1702, Tab. xxi. as Belemnites minor cinereus ari pistillum refe- 

 rens; the shelled belemnite of Grew, Rarities of Gresham College, PI. 20; 

 Belemnites sulcatus niger major, of Langius, Hist. Lap. Helv. Tab. xxxvu. 

 Fig. 3 ; Utrinque perquam acuminatus of Baier, Oryct. None. Tab. i. 

 Fig. 7 ; and others similar, he conceives, should be considered as spines 

 of echini, and similar to those which he received from Studtgard : but 

 those fossils which possess the conical cavity, the canalicula, and the 



VOL. Ill, O 



