ON DOEYPTERUS HOFFMANNI. 255 



column ; but in all our specimens this part of the fish is injured. 

 The lateral plates are narrower than those lower down the body, 

 and apparently gradually subside into the columns, without any 

 distinguishing point. 



These lateral plates at this point incline forwards ; the few 

 next lower down are much inclined backwards ; so that there is 

 here a large space over the abdominal region devoid of all such 

 appendages. In all the four specimens this is the case, as well 

 as in the German specimens above referred to ; and it is there- 

 fore probably the natural condition, and is not owing to acci- 

 dental circumstances, though it is possible enough that pressure 

 may have had something to do in forcing the plates asunder. 



The ventral plates (m) extend from the root of the ventral fins 

 to almost the commencement of the anal ; and from the lower 

 part of the posterior plate there is a stout rod or process (o) ex- 

 tending upwards and backwards as far as the outer extremities 

 of the lateral plates. Below, this process is wide and flattened ; 

 above, it is cylindrical ; and at the point where this change takes 

 place it is obtusely angulated backwards, the whole being a little 

 arched in the same direction. There are apparently two of these 

 great abdominal rods or processes, one belonging to each side, 

 giving support probably to the lower posterior boundary of the 

 abdominal walls, and limiting in this direction the naked space 

 above alluded to as extending over the lateral walls of the abdo- 

 minal chamber. These two stout rods are closely pressed toge- 

 ther, and in all the specimens are much confounded with each 

 other. 



Above the median line, in front, the outer members of the 

 series of transverse plates and rods are likewise considerably 

 modified. The change takes place gradually, just behind the 

 elevated portion of the dorsal fin. The lateral plates (fig. 3, g), 

 however, are only slightly modified ; but instead of being united 

 to rods are continued as broad flat plates (%), which, inclining 

 forwards, become angulated in front, and then for a short dis- 

 tance (j) incline backwards, and are united to a series of hour- 

 glass-shaped plates (k) that lean in the opposite direction, are 

 extended to the dorsal margin, immediately below the anterior 



