118 LIVERPOOL BIOLOGICAL SOCIETY. 
To this list I have now to add— 
7. Monstralla longicornis, n. sp., 
a form of which I recently took one specimen near- Puffin 
Island, and which differs specifically from the six previously 
enumerated. Considering our still very limited knowledge 
of the genus it 1s by no means improbable that further 
investigation may reveal the necessity of dividing Mon- 
strilla mito two genera. Indeed Claparéde says*: ‘‘One 
can still be doubtful whether the Chinese M. viridis and 
the European species really belong to the same genus.” 
Bourne ingeniously founds a system of classification of 
the species of Monstrilla upon the number of sete occurr- 
ing on each division of the caudal segment, 
viz., A, Three sete on each furcal member. 
B, Six setee i 5 Fs 
Claparéde, however, in his exceedingly beautiful plates, 
figures (1. c. fig. 2) the male of Monstrilla dane with four sete 
on each furcal member, Mr. Bourne’s supposition bemeg 
that ‘‘he has omitted to count them carefully.” I think 
it is probable that Claparede is quite correct on this point 
both from the fact of his generally careful description and 
because my specimen of JM. longicorns has undoubtedly 
four sete, and only four, on each furcal member. If, 
therefore, the number of caudal sete is found to be 
sufficiently constant for this basis of classification to be 
retained, 1t will be necessary to add a further division :— 
C, Four setz on each furcal member, 
containing M. dane of Claparede and my new species 
M. longicornis. I suspect, however, that it will be found 
necessary to discover some more stable basis for the 
classification of the various species composing this most 
remarkable and altogether puzzling genus. 
WIE; Cita ja SG 
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