THE APODOtTS HOLOTHURIANS 41 



coast of Georgia, lat. 32 40' N., long. 76 40' 30" W. (Cat. No. 14726, U. S. N. 

 M.). The general appearance and the tentacles are exactly like the other Mol- 

 pudids, and the absence of true pedicels confirms the relationship to those 

 forms, especially since Gerould ('96) has shown the presence of rudimentary 

 subcutaneous pedicels in Caudina arenata. The papillae in Himasthlephora are 

 shown by sections (figs. 3 and 4) to be provided with ampullae, which are con- 

 nected with the radial canals, but the rudimentary pedicels do not seem to have 

 any such connection. The radial canals, moreover, apparently terminate at the 

 base of the tail instead of at the tip, as in Caudina, although in neither of the 

 two specimens sectioned was this positively determined. In the form and ar- 

 rangement of the longitudinal muscles (see the section of one in fig. 4) there 

 is a resemblance to the Synaptidae; but as a very similar arrangement occurs 

 in Eupyrgus (Plate XII, fig. 27), it is not unique among Molpadids. It is very 

 probably a primitive character, retained by Himasthlephora, which on the 

 whole is apparently nearer the pedate ancestor of the apodous holothurians 

 than any of the genera hitherto known except perhaps Gephyrothuria, its rela- 

 tion to which is discussed on page 184. 



