304 



DISCOVERY REPORTS 



the limb arrangement. Figs, i and 2 are detailed drawings based on the lateral and 

 ventral photographs. 



After as complete a study of the whole specimen as I could make, I embedded it in 

 paraffin wax and sectioned it parasagittally down to the middle plane. The remaining 

 half was dissolved out of the wax by xylol and transferred back to spirit. In this way 

 I have obtained a series of sections from which it will be possible to study, to a certain 

 extent, the internal anatomy. But, more important, in the remaining whole half, I was 

 able to view the limbs from the median aspect, and without this view I maintain that in 

 most Crustacea it would be useless to speculate as to the method of functioning of the 

 limbs. I have not drawn a figure of this view as the overlapping of the setae would have 

 obscured the essential details. In Fig. 4 I have drawn a series of figures showing 

 separately the median aspects of the mouth parts, the first, second and part of the third 



Fig. I. Nebaliopsis iypica. Side view. 



trunk limbs. This series can be compared with the corresponding figures of Nebalia 

 which I have already published (1927, p. 361, Text-fig. 4). 



The antennules, antennae and mandibles have been described in sufficient detail by 

 Thiele (1904) and I have nothing further to add beyond what I have already described. 



The maxillule, as Thiele states (1904, p. 21), is two-jointed, the palp being reduced 

 to a small stump. This is not, however, blunt as in Thiele's figure (PI. 3, fig. 48) but 

 terminates in a feathered spine about as long as the palp itself (Fig. 3). The arrangement 

 of the two endites shows a similarity to that of other Malacostraca but has been dis- 

 torted by the flattening out of the region immediately behind the mouth. In Nebalia 

 the lower lip is deeply cleft into two marked paragnaths. The setae of the proximal 

 endite curve round behind the latter and point directly into the mouth as in all the 

 primitive Malacostracan groups. The setae of the distal endites bite together in the 

 middle line immediately underneath the paragnaths (Cannon, 1927, p. 364, Text-fig. 7). 

 In Nebaliopsis the paragnaths have become flattened out into two indistinct ridges run- 

 ning parallel to the median plane, and, in so doing, appear to have pushed the maxillules 



