ACIPENSER HECKELII. • 405 



shaped scales on the throat are densely packed in rows, but are embedded in 

 the skin. The strong bony ray o£ the pectoral fin is longer than in A. 



Acipenser heckelii (Fitzinger). 



This short-nosed Sturgeon, with a rounded snout, is found in the Adriatic 

 sea and river Po. It is more frequently met with than A. aaccarii, and is 

 known in Venice as Cope.se, but nothing is definitely ascertained of its habits 

 or life-history. Dr. Giinther regards it as a variety of A. giiUlemtddti'i, but 

 the differences from that type are strongly marked, although there is a close 

 genei-al resemblance. It varies in length from eighteen inches to four feet 

 and a half (Fig. 194). 



The colour of the head is black, and the upper part of the l)ody is blackish. 

 The lower part of the body and shields are dirty white. 



The head measures one-fifth of the entire length. The fish is eight and 



Fig. 194. — ACII'ENSEK HECKELII ( FITZIN<!EK) . 



two-thirds times as long as high. The height and breadth are equal. The 

 form of the head is similar to that of A. guldemtiidtii, but shorter, and 

 the contour of the snout, seen from above, is semicircular. 



All the shields of the head are comparatively flat, finely rayed, granular, 

 and closely packed together. The supra-occipital is narrow in front, expanded 

 laterally in a broad V-shape, and notched behind to receive an anterior process 

 of the first dorsal shield (Fig. 195). 



The epiotic shields are longer than wide, but broad and sub-hexagonal ; 

 each abuts against the first dorsal, the supra-occipital touches the parietal by a 

 narrow margin, and penetrates into the squamosal with the anterior angle. 

 The parietal shields are long, and entirely separated from each other by a series 

 of ethmoid ossifications, the posterior of which divides the extremity of the 

 supra-occipital shield ; the squamosal shields are broad and short. Their 

 centres are well behind the centres of the parietal shields, and in a line with 

 the anterior termination of the supra-occipital shield. The frontal shields are 

 broad, but do not extend to the orbit, which is margined above and behind in 

 the usual way by the broad post-frontal shield, which extends farther back 



