VIVIPAROUS FISHES OF THE PACIFIC COAST. 
475 
Fig. 86. A larva 0'85 mm. long, showing the thick caudal lobe. The yolk vesicle is evident in the 
posterior end of the yolk. 
Fig. 87. A larva IT mm. long; the heart is now formed. 
Fig. 88. A larva 1-2 mm. long, showing the first gill-slit, through which the nourishment is now taken. 
Fig. 89. Outline of the circulation in the head of a larva older than fig. 91. 
Fig, 90. A larva l - 8 mm. long, showing the enormous yolk sack, of which the yolk occupies but a very 
small part. The posterior wall of the pericardial chamber is here pushed much too far 
forward, a condition due to partial asphyxiation. 
Plate UIV. 
Fig. 91. Enlarged head of a slightly older larva than that of fig. 90, in which the liver l has been 
partly formed and the aegmentation of the hind brain has become very conspicuous. 
Fig. 92. Outlines of the circulation in a larva about 2 mm. long. 
Fig. 93. A larva 4 mm. long; the liver is well formed and the yolk yk lies at its lower anterior angle. 
The segmentation of the hind brain is evident; Canada balsam preparation. 
Fig. 93a. Relation of liver to intestine in a larva 32 mm. long. 
Fig. 936. The relative size of the fore and hind guts in the same larva. This difference is reduced 
during the growth of the next 5 mm, in length, larva} 37 mm. long, showing the condition 
seen in larvae 45 mm. long. 
Fig. 93c. The intestine in a fish 45 mm. long. 
Fig. 93d. The same in a fish 62 mm. long. 
Fig. 93c. Diagram of the loops of the intestine of the largest fish observed, 160 mm., in which an extra 
dorsal loop had developed. 
Fig. 93/. One of the villi of the hind gut, much enlarged, from a living specimen 10 mm. long; showing 
the vascular loop. 
Fig. 94. A larva 5 mm. long ; the pectoral is formed ; long ridges have appeared on the inner surface of 
the hind gut ; these are later transformed into papilla}. A fin fold runs along the tail, above 
and below; the pericardial chamber has been greatly reduced. 
Fig. 95. The tail of another larva more enlarged, showing the tip of the notochord and the first indi- 
cations of the caudal fin. _ 
Plate CV. 
Fig. 96. An older larva. The tubular heart of fig. 94 has been transformed into the three-chambered 
auricle, ventricle, and bulbus arteriosus. 
Figs. 97 and 98. Slightly older larvse than fig. 96. 
Fig. 99. A larva 8 mm. long; the definitive fins of the adult have begun to develop. 
Fig. 100. Another larva younger than fig. 99. 
Fig. 101. A larva 10 mm. long. 
Fig. 102. A larva 11 mm. long. 
Fig. 103. A larva 12 mm. long. 
Fig. 104. A larva 13 mm. long. 
Fig. 105. A larva 16 mm. long. 
Plate CVI. 
Fig. 106. A larva 23 mm. long. 
Fig. 107. A larva 22 mm. long. . 
Fig. 108. A larva 34 mm. long, shortly after birth. 
Fig. 108a. Adult female of Cymatogaster aggregates. 
Fig. 1085. Adult male of Cymatogaster aggregates. 
Plate CVII. 
Figs. 109, 110, 111, 112. Four sections, slightly oblique, of a larva but little more advanced than the 
stage figured in 75, and taken from the same ovary. The larva is straighter than 75, and the 
sections can not be represented as parallel planes in that figure. The embryo was cut into 
42 sections. Fig. 109 is 4 sections behind the origin of the notochord or the 14th from in 
front backward. Fig. 10 is the 22d section, fig. Ill the 29th, and fig. 112 the 30th section of 
the same series. This series represents the extent of the hypoblast in different regions of 
the body and the character of the evaginations to form the gills. This evagiuation extends 
through 19 sections in this series. Hypoblast shaded. 
