80 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 105 



Whole mount features: Th'e larger specimen is 27 mm. long by 16 

 ram. wide, broad anteriorly and narrower posteriorly (fig. 5) but it 

 obviously has been distorted by fixation. The margins are rufiied 

 and much damaged. At the anterior end are the usual two tentacles 

 formed by upfoldings of the margin. On account of the black color 

 here, the eyes on the tentacles could not be seen, and the same is 

 true of the cerebral eye cluster. The ground color appeared to be 

 a pinkish orange; there is a dense black border dotted with white 

 dots. On the dorsal surface is a pattern of dark bars arching trans- 

 versely from a middorsal strip of the same color. This dorsal pattern 

 is also liberally strewn with spaces of the same color as the background. 

 The pattern was intact only in the anterior part of the worm and was 

 more or less destroyed by mjmy posteriorly; consequently, it is not 

 certain that the same pattern obtained over the entire dorsal surface, 

 although this appeared to be the case. The pharynx was not clearly 

 evident but appeared small and of rounded shape with a few heavy 

 folds. The male apparatuses are double in this species, and two 

 hillocks bearing the male pores are clearly in evidence at the posterior 

 border of the pharynx as shown in figure 5. Shortly behind the male 

 pores, in the median ventral line, is seen the female gonopore, and some 

 little distance behind that is found the sucker. 



The smaller specimen is of more rounded oval shape, about 12 mm. 

 long. It seems probable that it is the same species as the larger one, 

 although I am a little uncertain of this. There is the same black 

 border with white dots as in the preceding specimen, and on the dorsal 

 surface there are black markings similar to the foregoing with many 

 open spaces in them. But here again the dorsal pattern is much 

 damaged and distorted. The two male pores are in evidence. 



Differential diagnosis: Pseudoceros micronesianus differs from 

 other species of the genus in the color pattern. 



Holotype: The larger specimen, preserved in alcohol, is made the 

 holotype (USNM 25947). The smaller specimen is also in alcohol in 

 the U. S. National Museum. 



' 'Remarks: The numerous species of the genus Pseudoceros^ most 

 of which inhabit the Indo-Pacific region, are at present distinguishable 

 almost wholly by the color pattern. In the absence of accurate color 

 notes accompanying the specimens, it is very difficult to identify the 

 species of this genus or to determine with certainty whether a new 

 species is at hand. Often the colors, very brilliant in life, disappear 

 altogether on preservation. I have, with some hesitation, considered 

 these specimens as representing a new species because what remains 

 of the color pattern appears to differ from that of previously described 

 species. The present species is one of those with a pair of male 



