322 



56 



in most (ishes is liiriied towards tlu' belly. Accordingly, the pnlîic bones (PI. VII, 

 tig. 3 p) are not lying tlal but stand upright. Those margins, which are usually 

 as inner margins in contact, are here not only free of each other but diverge, 

 pointing upwards and outwards; whereas those margins, which are usually the 

 outer margins and diverge, here converge and (nearly) meet ventrally. Each pubic 

 bone forms a large erect plate somewhat inclined from the mid -ventral line 

 towards the lateral body wall ; it is thick behind where the ventral rays are 

 attached, extremely thin at the upper and anterior margins. The interior is to a 

 great extent cartilage, and the lower anterior part is almost unossified. The outer 

 surface carries a strong crest (cr) dividing between the muscles to the lowermost, 

 spinous, ray and those to the other rays; above and parallel to this crest a smaller 

 and less prominent one is found in addition. The upper margin of each pubic 

 is firmly joined to the lateral body-wall (especially through dense connective tissue 

 to the inside of the second dermal scute from below in the posterior transverse 

 thoracic row); the lower margin of the anterior part joins the median ventral scute, 

 here meeting its fellow from the opposite side. The posterior ventral corner (*) of 

 the thick hind part is tightly fastened to the inside of the lowermost scute of the 

 last row of the thorax. In this way the skeletal support of the ventral fm-muscles 

 is strengthened'"'. 



Of the 7 rays in the ventral fin the outer (lower) is an undivided spine; the 

 remaining 6 are biramous, the two main branches parting nearest lo the base in 

 the innermost (uppermost) rays. Each of the two main branches is again longi- 

 tudinally split, but the two halves are tightly pressed together. Indistinct traces 

 of a transverse articulation are visible. In the female some of the peculiar thread- 

 like appendices for retention and nutrition (?) of the eggs and young are ossified; 

 these ossifications appear as rather long, slender branches from the divided rays, 

 except the uppermost one; they are generally twisted in a corkscrew-like manner 

 and end in a small rounded knob; (counting from below the 2nd ray carries 2, 

 the 3rd 3, the 4th ô, the 5th 4, the 6th only 1 of these osseous branchlets in an 

 old and large specimen of S. cyanopterus in my possession) 



Number of fin-rays in the specimens examined. 



