76 The Ohio Journal of Science [Vol. XIX, No. 1, 



Concerning Possible Locomotion. 



These animals are usually considered sessile and of course 

 there is no direct evidence as to their locomotion. It is, how- 

 ever, possible that they may have been able to move and this 

 is suggested by Clark, 1901. 



The specimens of A. aiistini from Cowan's Creek are usually 

 found unattached and aboral side up. This may be merely 

 evidence of the loosening from the shell on which the animal 

 had lived after its death. 



The material from Lawshe shows clam valves with numerous 

 young specimens, Fig. 20, and valves with fewer larger speci- 

 mens. Fig. 24. It is possible that as valves were overcrowded 

 some died and dropped off and the survivors occupied their 

 space; but it is also possible that they simply moved away as 

 they outgrew the place of attachment. 



Dr. G. H. Parker has shown for gastropods that animals 

 which show no pedal waves still may have the same type of 

 muscular movement in a different form which will result in 

 locomotion. 



Furthermore, he finds the same type of locomotion illustrated 

 in the Actinians among the Coelenterates, resulting in the case of 

 Condylactis in an advance of more than a centimeter in three 

 minutes. 



P solus fabricii, the recent holothurian, already referred to 

 with reference to the peripheral rim, has a muscular "sole" 

 which may be of much the same type as the aboral attachment 

 of A gelacrinites . In spite of the distant relationship between 

 these two forms, why may not the close parallelism between the 

 skeletons of the two, be accompanied by the same ability to 

 creep in the A gelacrinites as the Holothurian has? 



Respiration. 



It is obvious that an animal whose body is protected by so 

 complicated a series of plates would not be able to breathe 

 easily directly through the outer wall. The clue for the 

 respiration is found in the related group of the crinoids. In 

 Antedon (Parker and Haswell, Vol. 1), the rectum projects as 

 the tubular papilla and the rectal tube is in the living animal 

 seen to undergo frequent movements of contraction and dilation 

 by means of which water is drawn into and expelled from the 

 rectum. There is thus intestinal respiration. 



