Fig. 67. Transverse section through the tail of an advanced larva, shewing
the neural and hæmal processes, the independently developed interneural and
interhæmal elements (_is_), and the commencing dermal fin-rays (_df_).
Fig. 68. Side view of the tail of a larva, 21 minims. in length, dissected
so as to shew the structure of the skeleton.
Fig. 69. Longitudinal horizontal section through the vertebral column of a
larva, 5.5 centims. in length, on the level of the hæmal arches, shewing
the intervertebral rings of cartilage continuous with the arches, the
vertebral constriction of the notochord, &c.
Figs. 70 and 71. Transverse sections through the vertebral column of a
larva of 5.5 centims. The red represents bone, and the blue cartilage.
Fig. 70. Through the vertebral region, shewing the neural and hæmal
arches, the notochordal sheath, &c.
Fig. 71. Through the intervertebral region, shewing the intervertebral
cartilage.
Figs. 72 and 73. Transverse sections through the trunk of a larva of 5.5
centims. to shew the structure of the ribs and hæmal arches.
Fig. 72. Through the anterior part of the trunk.
Fig. 73. Through the posterior part of the trunk.