133 



disk. Most of the rods in the tentacles as well as those in the 

 oral disk have a very characteristic rough surface, as mentioned 

 by Fisher. Besides, the rods in Opheodesoma are not more than 

 ca. 80 fi long and those in Euapta may be ca. 280 \i long. 



The geographical distribution of the genus Euapta is very 

 interesting as the one group of species is Indo-Pacific and the other 

 West-Indian. Only one specimen is reported from the West African 

 Coast (Théel in the "Challenger" Report) but the specific deter- 

 mination of it {lappa) cannot be regarded as quite certain. 



The two old-known species godeffroyi (Semper) and lappa (Johs. 

 Müller) are distinctly different, and easily separated. Furthermore 

 polii (Ludwig) is a distinct species, not synonymous with lappa as 

 supposed by Clark. One of the best characters separating polii 

 from lappa is the lacking of the web between the digits, which is 

 present in lappa. The specimens described by Clark in „The 

 Synaptinae" as lappa, are most likely specimens of polii, since 

 Clark states the web between the digits to be wanting, and his 

 measurements agree pretty well with Ludwigs figure of the 

 anchor-plate in polii. The specimens at hand of lappa and toba- 

 goensis Heding have all a distinct web between the digits, and are 

 thereby easily separated from polii, which is not represented in 

 the collection. 



Of the Indo-Pacific group there are six specimens from Hawaii. 

 Five of these are typical specimens of godeffroyi Semper, but one 

 differs distinctly from the others. It is described as a new species 

 and on account of its large size named magna. 



Key to the species of Euapta. 



1. West-Indian species 2 



Indo-Pacific species 4 



2. Web wanting between the digits polii 



Web present between the digits • 3 



3. Rods in oral disk different from those in tentacles, having the ends 

 unbranched. Articular end of anchor-plates of varying shape and side- 

 holes often wanting tobagoensis 



Rods in oral disk as well as those in tentacles with distinctly branched 

 ends. Side-holes large and always present lappa 



4. Web present between the digits godeffroyi 



No web between the digits magna 



