﻿406 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 102 



b^. Nophridiopores well spaced behind anus. 



cK Polian tubules very long; retractors arise posteriorly. 



<f'. Size small; gonads on surface of retractors near their origin; F* at- 

 tached to intestine only lissum, new species 



d^. Size large; gonad on body wall just back of origin of retractors; F' 

 anchors both intestine and postesophageal gut. 



schmitti, new species 

 c'. Polian tubules short; retractors arise in middle region of body; size 



large (230 mm. in length) dehamata Kesteven 



0*. No hooks on introvert; 4 retractors; tentacles ?; contractile "vessel bears a 

 band of very short contractile villi" stephensoni Stephen 



KEY TO SPECIES OF DENDROSTOMUM DESCRIBED IN THIS PAPER 



o'. Hooks or spinelets on introvert. 



6'. Tentacles arising from 4 roots; hooks smaller; fixing muscle F^ attached 



to postesophageal intestine pyroides Chamberlin (p. 406) 



b^. Tentacles arising from 6 roots, hooks larger; fixing nuiscle F* with one 

 branch to postesophagus, the other to intestine, or to intestine only. 



hexadactylum Sato (p. 410) 

 0*. Hooks absent from introvert. 



bK Anus and nephridiopores on nearly same level; tentacles 6; upper lip 



larger than the other three; nuchal organ not longer than wide. 



c'. Intestinal spiral of moderate length with less tlian 50 coils; fixing 



muscles of alimentary canal present; skin glands of approximately 



same size. 



d'. Fixing muscle F^ attached to postesophagus; retractors attached 



one-fourth to one-third body length from posterior end; nuchal 



organ wider than long zostericolum Chamberlin (p. 411) 



d^. Fixing muscle F^ attached to intestine; retractors attached one-fifth 

 to one-sixth body length from end; nuchal organ not obviously 



wider than long dyscritum, new species (p. 417) 



c*. Intestinal sjjiral very long with upward of 100 coils; fixing muscles 

 usually absent; skin glands of two or three sizes. 



perimeces Fisher (p. 415) 

 b^. Nephridiopores well spaced behind anus; tentacles 4; upper lip not con- 

 spicuously larger than others; nuchal organ longer than wide, 

 c'. Size small; gonad on surface of retractors near origin; dorsal tentacles 

 not conspicuously smaller than others; fixing muscle F^ attached to 



intestine lissum, new species (p. 419) 



c*. Size large; gonad on body wall just back of origin of retractors; F^ 

 anchors both the postesophagus and intestine with branches to each; 

 dorsal tentacles much smaller than the others. 



schmitti, new species (p. 422) 



DENDROSTOMUM PYROIDES Chamberlin 



Plate 27, Figures 1, 2; Plate 28, Figure 2; Plate 29 



Dendrostoma pyroides Chamberlin, 1919, p. 31. 



Dendrostoma petraeum Fisher, 1928, p. 195, pi. 6, figs. 1, la, lb, 2; pi. 7, fig. 2; 



pi. 8, figs. 1, la. 

 Dendrostoma blandum Sato, 1930, p. 27; 1939, p. 412. 



Diagnosis. — Typically a large, elongate-pja-iform species with 

 smooth skin and a zone of from few to many small, usually curved, 



