Klem — The Development of Agarkocrinus. 179 



ent time, and we may safely assume that the same rules of 

 distribution which exist to-day existed during the geological 

 ages. From Florissant, Colorado, a place famous for the 

 great abundance of fossil plants and insects found there, 213 

 species of fossil plants have been enumerated.* Of these the 

 Family Myricaceae contains the largest number, thirteen in 

 all. More than one hundred and seventy species of Formi- 

 cidae have been described from different localities, the largest 

 number, thirty-seven, from Radoboj. 



(c) Possible influence of light. — The aerial parts of plants 

 are directed largely under the influence of light, the stem and 

 petioles curving toward the light and the blades standing at 

 right angles to the rays of light. Gorgonia shows the same 

 tendency to develop more on the side toward the light, and in 

 a number of Blastoids the whole body leans considerably to 

 one side, suggesting more rapid development toward the light. 

 In a number of Crinoids the same asymmetry of the calyx 

 may be seen, which may be due to heliotropism. As to the 

 extent of this influence it is impossible to come to any definite 

 conclusions at the present time, but a thorough study of 

 more material mav lead to more tangible results. 



( d ) Effects of injury . — In describing Batocrinus insuelus] 

 Miller gives as one of the distinctive characters the balloon- 

 shaped bulb terminating the proboscis. This is as far as I 

 know the only one found having this feature, which alone 

 should have made the author very cautious about describing 

 it as a new species. In all probability the proboscis was 

 injured early in its growth, and as a result developed a balloon- 

 shaped growth. There is no more reason for making a new 

 species based on this character, than there would be for 

 creating a new species of oak, because the tree had a part of 

 its trunk expanded into a big tuber-like growth. Very many 

 Crinoid stems show the marks of injury and an increase in 

 size at those points. 



The mistake of considering the variations in the different 

 parts as of specific importance has led to the creation of many 



* Trans. The Academy of Science of St. Louis. 8 : 161-188. 

 t Bull. 111. State Mus. Nat. Hist. 7: 14. pi. I. f. 8, 9. 



