4-24 
ZOOLOGY OF THE FAR EAST. 
Sub-order VALVIFERA. 
Family IDOTEIDAE. 
While it is comparatively easy to decide that the species described below is new 
to science, it is a much more difficult matter to determine to which of the existing 
genera of the family it should be referred. In my endeavours to arrive at a proper 
conclusion of this question I have encountered many discrepancies in existing generic 
definitions and have experienced much of the confusion which still exists in this 
family, in spite of the work of recent authors. There is much diversity of opinion 
and no little inconsistency as to what constitutes a generic character and it is not an 
infrequent experience to find one character used as a basis for generic separation in 
one group of species and as cheerfully ignored in another group by the same author. 
Much of the existing chaos is due to the imperfect descriptions given by earlier 
authors and as these early species are retaken and recognised and their diagnoses 
brought up to date in the light of accummulated knowledge, order is slowly evolving 
itself out of the confusion. But much still remains to be done, and a thorough 
revision of the family is needed. ' This is not the place to attempt to do this, for the 
material at my disposal is inadequate. But I may perhaps be allowed to point 
-out some of the discrepancies and inconsistencies which I have encountered in 
my search through the literature, in the hope that some other worker with more 
abundant material may eventually elucidate my difficulties. 
Collinge (1918) in a paper on the oral parts of the Idoteidae has summarised the 
existing genera of the family in a table, giving the number of spines on the inner 
lobe of the first maxilla, the number of joints on the palp of the maxillipede and the 
number of complete segments and sutures in the metasome. 
Excluding the Glyptonotinae and Mesidoteinae and the anomalous genera 
Symmius, Richardson and Chiriscus, Richardson, we find that the remaining genera 
in Collinge' s table may be grouped into three divisions according to the number of 
joints in the palp of the maxillipede, as follows: — 
Pai^p of the MaxiIvLipede five-jointed. 
Z enobiana, Stehhing ; Pentidotea, Richardson ; Engidot:a, Barnafd ; Cleantidla, 
Richardson ; Paridotea, Stebbing ; Glyptidotea, Stebbing ; Pentias, Richardson ; 
Crabyzos, Spence Bate. 
PAI.P OF THE Maxillipede four-jointed. 
Idotea, Fabricius; Euidotea, Collinge; Colidoiea, Richardson; Eiirymmenis, 
Richardson ; Erichsonella, Benedict ; Synisoma, Collinge. 
Palp of the Maxillipede three-jointed. 
Edotia, Guer.-Men. ; Synidotea, Harger. 
Our species falls into the first of these three groups in having the palp of the 
maxillipedes five-jointed. The genera in this group are separated from one another 
mainly on the characters of the segmentation of the metasome. I reproduce here 
that part of CoUinge's table which deals with this character. 
