NO. 3 BURGESS SHALE FOSSILS WALCOTT 3 



leathery as it is a black film with irregular, broken, longitudinal lines 

 with more or less scaly edges. 



Microscopic structure undetermined. 



Observations. — The perforations in the tegument are not unlike 

 those of the living alga Agarmn turneri Post and Ruprecht, and one 

 might imagine that a fragment of the strong frond of this species 

 is similar to M. dorus, but the resemblance is only general ; the per- 

 forations of M. dorus are more uniform than those of the beautifully 

 perforate living alga Kallymenia perforata Agardh, which also has a 

 far more delicate tegument. 



llolotype and paratypes. — U. S. N. M., Nos. 83922, 83923a-e. 



REDOUBTIA Walcott 1918 

 REDOUBTIA POLYPODIA Walcott 



Plate 2, figs. 2-2, 



Rrdniihtia polypodia Walcott, igi8, .Smithsonian Misc. Coll., vol. 68, no. 12. 

 P- 5, fig- 5- 



The hulotype is refigured since it was first published in the popular account 

 of field explorations issued annually by the .Smithsonian Institution, which does 

 not reach paleontologists generally. 



Accompanying the original figure is the following statement, "An elongate 

 creeping holothurian with numerous tube feet and tentacles." 



Whether the second specimen really represents the same species appears some- 

 what doubtful inasmuch as the tube feet are smaller and more numerous. The 

 larger appendages above the specimen, as posed on the plate, are parts of 

 another animal. 



Holotype and paratypc. — U. S. N. M., Nos. 83924 and 83925. 



PORTALIA Walcott 1918 

 PORTALIA MIRA Walcott 



Plate 3, figs. 2-3 



Portalia niira Walcott, 1918, .Smithsonian Misc. Coll., vol. 68, no. 12, p. 6, 

 figs. 6, 7. 



Another holothurian first figured in the explorations account for 1918 is also 

 refigured, to give it wider availability. This form differs from the preceding 

 Redoiibtia polypodia in having fewer and longer tube feet and in their ai)parently 

 different grouping. 



Holotype— LI S. N. M., No. 83927. 



