THE ELENNY FAMILY, 213 



where the ventral embryonic fin joins the yolk-sac. De Filippi 

 had formerly shown that in the twaite-shad the gall-bladder lay 

 behind the yolk, but the liver in this instance did not pass 

 downward. The breast-fin is somewhat fan-shaped, very thin 

 (membranous), and stands erect. The other structural features 

 are of great interest, and have been already published by 

 one of us in conjunction with Prof Prince'. The mouth is 

 open, but only tremors of the lower jaw are noticeable, aeration 

 being much aided by the exposed condition of the gills. The 

 eyes have a silvery lustre with a black pupil. A few black 

 pigment-corpuscles occur over the upper curve of the eye 

 anteriorly, and this region shows a fine green shade like 

 malachite. 



In a fortnight, finely branched black pigment is seen over 

 the coiTugated gut posteriorly, and smaller specks as far forward 

 as the yolk-sac, and backward along the edge of the muscle- 

 plates. A few also appear over the yolk-sac. The larvas 

 exhibited a tendency to lie on their sides at the bottom of 

 the vessel, a feature, indeed, they showed after the lapse of 

 five weeks. 



At the latter date a well-marked ventral line of pigment 

 runs from the heart to the vent, passes forward and upward 

 behind it, and is then continued to the tail. This pigment 

 anteriorly ceases before reaching a line from the breast-fins, an 

 oblique bar on each side, forming a A with the apex directed 

 forward, occurring in this region, only a short streak of pigment 

 existing in the middle line in front. No trace of ventral fins is 

 apparent. The body is surrounded by a marginal fin — dorsally 

 deepening a little in front of the tail, which in outline is 

 somewhat lobate. Embryonic fin-rays are present in the tail 

 and in the breast-fins. The snout extends about half the 

 diameter of the eye in front of it, and the lower jaw projects 

 a little further, but is motionless, aeration of the gills being 

 accomplished, as in many other larval fishes, by their active 

 progress through the water. The large size of the ear-capsules, 

 which nearly meet in the median line dorsally, is an interesting 



' Op. cit. p. 868. 



