868 PROFESSOR W. C. M‘INTOSH AND MR E. E. PRINCE ON 
of the yolk (y) and the thin yolk-sac (ys). The oil-globule (og) seems to lie in a pocket 
in the cortex of the yolk, as an equatorial line crosses over it, yet it is also enveloped 
by a complete protoplasmic covering (p). The gall-bladder (gb) occupies, in the upper 
posterior portion of the liver, a position just at the angle where the ventral embryonic fin 
(ef) joms the yolk-sac. As first shown by Dx Frurepr,* the gall-bladder of the larval 
Clupea finta lies also behind the yolk ; the liver, however, does not in this instance pass 
downward. The pectoral fin (pf) is somewhat fan-shaped, very thin and membranous, 
and stands erect ; while a chitinous clavicle (c/) is fixed by a longitudinal lateral attach- 
ment. The long intestine, with a distinct rectal portion, curves downward a considerable 
distance from the yolk, and cuts off, by the anal protrusion («), a ventral fin-area about 
one-third the length of the inferior embryonic membrane. The lumen of the alimentary 
canal is spacious and the walls much folded, but that of the cesophageal section is very 
much diminished. A valve or cincture marks the commencement of the rectum (hg). 
The segmental duct (sg) is plainly seen passing from a convoluted pronephric portion 
(with oval glomerulus, g/), with an undulating course to a spacious urinary vesicle (wv), 
which opens close to the anus (a). The notochord (nc) is fairly straight, but in the 
mid trunk it ascends by a gentle curve and gently bends round, to end between the 
posterior limits of the two eyes. It has the usual large irregular cellular structure, and 
presents a distinct perichordal sheath (pes). The heart (h, Pl. XIII. fig. 5) is fully 
formed, showing a rounded ventricle, which gives off, in front, a narrow bulbus directed 
upward, and behind receives the large vase-shaped auricle, opening into a wide sinus 
venosus. ‘The pericardial chamber (pd) is large, and its floor is entirely free from the yolk. 
The oral and branchial cartilages are well developed (Pl. XIII. fig. 5). The mouth is 
widely open on emergence, and water freely enters. Only tremors of the mandible, 
however, are noticed. The mandible (mn) is as usual a massive cartilage with an 
enlarged articulating extremity, joined by two cartilages from above, the anterior or 
quadratopterygoid (ptg), and a more massive hyomandibular (hm), which springs by a 
large base from the floor of the ear-capsule (aw). Four acutely curved branchial cartilages 
(bra) are present, and the long hyoid cartilage (hyd) ends in a copula, which projects as 
a nodular eminence on the under surface of the mouth. The maxillary elements cannot 
be made out, but the front margin forms an overhanging upper lip. The parts of the 
brain are well marked,—the fore brain (fb), on the lower anterior face of which are 
laterally placed the nasal sacs (07), the pineal gland (pn), and the large dome-shaped mid 
brain (mb), with the cerebellar fold (cb) behind. The eyes haye a silvery lustre, with a 
black pupil. A few black pigment-corpuscles occur over the anterior superior curve of 
the eye, and this region shows a fine green shade like malachite. 
The structure of the ear is very complex, and the two otoliths seem to lie in the same 
anterior ampulla. 
The marginal fin (ef) commences very gradually between the ears, 7.e., posterior to 
he cerebellum, and it does not become very wide, although its depth is somewhat increased 
* Ann. des Sct. nat., 3™° sér., vil. p. 66, pl. i. fig. 1. 
