NO. 1876. ON THE CRUSTACEAN ORDER CUMACEA—CAL^IAN. 671 



nearly straight and vertical and is defined below by a strong antero- 

 lateral tooth. On each side of the carapace are four oblique ridges; 

 the first ridge does not pass on to the dorsal surface above, and near its 

 lower and anterior end it is bent upward at a right angle to pass on 

 to the side of the pseudorostrum; the other three ridges are parallel 

 to one another, the second ending below on the antero-lateral tooth 



Fig. 100.— Colueostylis (7) occidentalis, female, from the side. 



and the other two on the lower edge of the carapace ; above, the second 

 and the fourth pairs of ridges are continued across the dorsal surface, 

 wdiile the third pan* bend forward to meet the second. The ocular 

 lobe is small, broader than long, and shorter than the line of junction 

 of the lateral plates of the pseudorostrum; there is no pigment, but 

 tliree rather large lenticular elements can be seen. 



101 102 



Figs. 101-103.— Colurostylis (?) occidentalis, female. 101, Anterior part of body from above; 



102, FREE thoracic SOMITES FROM THE SIDE, PLEURAL PLATES OF THIRD SOMITE PARTLY CUT AWAY; 



103, ANTENNULE. 



The first free thoracic somite is only exposed on the dorsal side, 

 its lateral portions being overlapped by the second somite. The 

 lateral plates of the second somite are greatly expanded and are 

 separated from the tergum by a deep narrow incision of the anterior 

 margin. The pleural plates of the third somite are also greatly 

 expanded, overlapping those of the second somite above and pro- 

 duced backward below. The third and fourth somites have a 



