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THE AMERICAN NATURALIST [Vol. XLII 



as the pedicels. Furthermore, in Holothuria floridana at first 

 the tentacles are provided with terminal suckers and these organs, 

 like the primitive pedicels, are used for locomotion, while in 

 feeding, as in the adult, they push food into the mouth. Admit- 

 ting that the distal anal papilla? are modified pedicels, I think it 

 is reasonable to consider the proximal oral tentacles as pedicels, 

 only much more modified in the adult, for their special functions. 



Ostergren imagines the primitive form, or ' ' Stammholothurie, ' ' 

 as having had a soft body-wall containing spicules, and with five 

 simple radial muscle bands, interrupting the transverse sheet of 

 muscle." It moved by contractions of the body, and ate slime. 

 The stone-canal was simple and opened on the outside of the 

 skin. There were many pedicels and either ten or twenty ten- 

 tacles without ampullae. The calcareous ring had five radialia 

 and perhaps five interradialia. The enteron was in three loops, 

 the third in the right ventral inter-radius. The blood system 

 did not expand into a rete mirabile. The posterior end of the 

 enteron developed as a respiratory cloaca but respiratory trees 

 were not present. There were no auditory vesicles. Ostergren 's 

 primitive form was most nearly related to the present Elasipoda, 

 and from it he shows how the five chief divisions of the class 

 Holothurioidea may have evolved. Ostergren employs as the 

 names of these orders, Elasipoda. Aspidochirota, Dendrochirota, 

 Molpadonia and Apoda (Synaptidse, Chiridotidae and Myrio- 

 troehidse), and then concludes with a general description of the 

 chief characters of each order. 



Charles L. Edwards. 



THE ENTEROPNEUSTA 

 Recent Literature on the Enteropneusta. 1. Systematic. — 

 Spengel has lately given the classification of the Enteropneusta 

 a thorough overhauling. 1 This accepted imperator in the knowl- 

 edge of the group recognized at the time 31 species, 9 genera 

 and 3 families. Since then 14 species and one genus have been 

 added. Nearly all the new ones have come from the Pacific 

 and Indian Oceans, these two enormous reservoirs of unknown 

 organisms, the exploration of which has but recently begun in 

 earnest. R. C. Punnett's report, The Enteropneusta in the 

 "Fauna and Geography of the Maldive and Laccadive Archi- 

 1 Die Benennung der Enteropneusten-Gattungen. Zoolog. Jahrb., 15 Bel., 

 pp. 209-218, 1901. 



