PLATE 81 B. 



P«ge 

 Pig. 1-4. EURYPTERUS LACTTSTRIS. 407* 



1. A specimen of medium size, lying with the dorsal side exposed. The carapace has been 



broken off, showing the inner side of the maxillary plates, the post-oral plate, and the 

 four anterior pairs of feet, which are obscured at their bases. The body is curved, and 

 the tail-spine directed forwards. The pnstuliform scales upon the back are in four rows 

 on the thoracic joints, and two slightly diverging rows on the abdominal joints. 



2. The last joint of the swimming foot, with the minute palette at the extremity. 



3. The seventh joint of the swimming foot, having the triangular chelate extension separated 



at the suture. 



4. The first articulation of the ventral side, with the organs attached. 



