﻿9 



47 



Fig. 



Ainplüsih 



piuiclulata. bp outline of base of pectoral tin. 

 I>etlering otherwise as in PI. I lif,'. 1. 



in the two species where the latter is large, hut for quite a short way in sciitata; 

 the ciorsal, curved margin seems to be a simple suture; in reality however the cl 

 is here continued in under the edge both of the dorsal plate II and of the supra- 

 clavicle as a thin lamella which reaches nearly to the ridge which forms the con- 

 nection with the vertebral column in this region. 



The dorsal spine in A. sculata (PI. I, fig. 1, T) is formed of a single, undi- 

 vided piece, sculptured like the dorsal plates with fine longitudinal lines and 

 intervening furrows; the anterior part 

 inserted between the dorsal plates is 

 somewhat flatter, the remainder is 

 rounded, graduating evenly towards 

 the posterior end, in cross-section ver- 

 tically oval; there is a furrow along 

 its ventral aspect occupied by the 

 membrane of the first dorsal fin, the 

 upper edge of which it supports. It 

 is somewhat variable in length in this 

 species, as also a little in its curvature. 

 In the other two species the dorsal 

 spine is more complex. In the first 



place, it has in these a spine articulated to its end, in reality a spinous ray (PI. I, 

 fig. 2, R); at the articulation are found some small bony pieces, one on each side 

 (Pl.I, fig. 2, Z)and one unpaired ventrally (PI. I, fig. 2, t); on these see further p. 56 (18). In 

 the second place, the spine is divided on both sides in the whole of its length by 

 a lateral suture into an upper and a lower part. Indications of this longitudinal 

 suture may sometimes be detected 

 in scutata. It is very natural to sup- 

 pose that the movable spine is a fin- 

 ray and thus to conclude that the 

 large dorsal spine supporting it must 

 in some way or another represent an 

 interspinous bone; this supposition has 

 been expressed by Günther; that the 

 spine represents however 2 interspi- 

 nous bones and the same two inter- 

 spinous bones in all the three species 

 has not hitherto been recognised; the 

 structure will be more closely discussed later (see p. 54 (16) et seq.). 



The dorsal armour thus includes at the same time parts of the inner skeleton, 

 namely parts of the shoulder girdle (scl and cl) and parts of the interspinous bones 

 (the unpaired, small anterior donsal plate in A. strigata and punctulafa, and the 

 dorsal spine in all three species). That these skeletal parts may appear from the 



I). K. 1). VUlensk.Selsk. Skr., 7. Række, naturvidensk of inatliem. Afd. VI. 2. 7 



Aniphisih' slrk/aUt 



in Hg. 2 and PI. I, fig. 1. 



