THE GEPHYREA OF JAPAN. 65 



THALASSEMA ELEGANS, n. sp. 



This highly interesting species will also be fully described 

 in a separate paper together with the preceding. Here I restrict 

 myself to giving only the most salient characters of the species. 



Externally the species looks very much alike Thalassema 

 tœnioides, though there exist remarkable differences in internal 

 structure. In size, shape and color it shows a far reaching 

 agreement with that species except as regards the proboscis. 

 This in the present species is 30-40 cm. long and 1.7-2 cm. wide, 

 and is of a bright yellow color which becomes deeper towards 

 the mouth. The ventral surface of its anterior portion, for a 

 length of 6-7 cm. is marked with a fine and irregular net-work 

 of a bright green color. As in T. tœnioides, there are found 

 on the body-surface longitudinal stripes of a pale yellow color, 

 which however number 10, instead of 5. The ventral hooks 

 show nearly the same size, form, color and position as those 

 of T. tœnioides ; but internally they are not joined by an in- 

 terbasal muscle. The circular muscle of the body-wall is 

 separated into more or less regular bundles. The segmental 

 organs are numerous (in one specimen 27 were counted) and 

 are distributed generally in groups of which there are 7 pairs, 

 each consisting of 1-3 segmental organs. Aside from the pair- 

 wise arrangement indicated, there seems to obtain no definite 

 order in the manner of the occurrence of single segmental organs. 

 They represent large elongate sacs, each bearing two compara- 

 tively short spiral lobes. The pharynx is joined to the body- 



