194 PROFESSOR CHARLES CHILTON ON THE 



Heller from O. rossii Walker. Monsieur CHEVREUX had also kindly sent me a specimen 

 of 0. obtusa Sars from Norway, and an examination of this showed that in size and 

 in all essential characters it was identical with the specimens of Anonyx chilensis 

 Heller, though the eye was less oval and more widened below, and hence more like the 

 specimens of O. rossii. Consequently I am forced to the conclusion that O. obtusa 

 Sars also belongs to this widely distributed species. 0. mitsculosa Stebbing was 

 described from a single specimen obtained from the south of Japan, and from the 

 description given I think there can be no doubt that it is the same as the other 

 forms already described. 0. abyssorum Stebbing is supposed to be distinguished from 

 the other species mainly by the more strictly chelate character of the second gnathopod, 

 and the figure of the Challenger specimen shows the palm much more produced than it 

 is in any of the forms I have already referred to, though, as I have pointed out, there is 

 considerable difference among them in this character. In all other points there seems 

 little to distinguish 0. abyssorum from the others, and, as mentioned above, STEBBING 

 has already given Anonyx chilensis Heller as a possible synonym of this species, 

 although the second gnathopod in that form can hardly be described as truly chelate. 



For some considerable time I was inclined to think that perhaps it would be wise 

 to keep 0. abyssorum as a separate species ; however, after having finished my exami- 

 nation of the forms already mentioned, I found in the Scotia collection a number of 

 specimens from Saldanha Bay in South Africa which in most points are quite similar 

 to 0. rossii, but in which the second gnathopod has the palm so much produced that 

 it could quite strictly be called chelate, as in 0. abyssorum Stebbing. 



If this form had agreed in other points with STEBBING'S O. abyssorum it would 

 confirm the opinion that this is a distinct species ; but this is not the case, for the first 

 gnathopod, instead of having the basos slender and the propod rather broad, as in the 

 type specimen, is somewhat stouter than usual, and differs also in having the propod 

 considerably narrowed distally, so that its palm is much shorter.* In it the eyes are 

 black, usually oval, though slightly widening below, and they vary in size and in the 

 amount of widening at the lower part. After careful consideration I think it best to 

 include this form also in the same species as the others, although they might perhaps 

 be looked upon as different variety, though not corresponding in all points with the 

 form described as 0. abyssorum by STEBBING. 



If all these forms are combined they must be known under the name of Orcho- 

 menopsis chilensis Heller, as that name has priority by mauy years. With regard to 

 0. cavimanus Stebbing, from the Kerguelen Islands, STEBBING himself has identified 

 it with 0. zschauii (Pfeffer) ; but, as I have shown elsewhere, PFEFFER'S species is quite 

 distinct in the shape of the dorsal process on the urus and in the greater stoutness 

 of the body and the character of the first gnathopod, and has been since redescribed by 

 CHEVREUX under the name Waldeckia obesa. 



* In the stout basos and in the character of the propod the first gnathopod in these specimens shows 

 considerable approach to 0. nodimanus Walker, but it lacks the tubercle present in that species. 



(ROY. soc. BDIN. TRANS., VOL. XLVIII., 476.) 



