THE SKULLS OF FISHES. 



] 93 



mentS (/.') appear, side by side, in the under region of the sheath. 

 These pass into the hinder part of the proper cranium, which is 

 a sort of cartilaginous box, closed in front, and through the 

 greater part of its roof, only by membrane, but complete behind, 

 where it arches over the myelon, and is perforated by tho 

 occipital foramen. The postero-lateral parts of this cranium 

 are dilated to give rise to the two oval auditory capsules (c), and 

 beneath these they are produced into two processes, h and /, 

 which have a common base, but diverge from one another 

 below. The process h gives attachment to a cartilage which is 

 connected with that supporting the tongue (i). The process/, 

 on the other hand, passing downwards and forwards, becomes 



Fig. 76. 



Fig. 70. — A, the skull of a Lamprey viewed from the side; B, from above (after Miiller). 

 — a, the ethmo-vomerine plate; 6, the olfactory capsule ; c, the auditory capsule; 

 d, the neural arches of the spinal column ; e, the palato -pterygoid portion ; /, the 

 hyomandibular and symplectic portion, and g, the quadrate portion of the sub-ocular 

 arch ; h, stylo-hyal process ; t, lingual cartilage ; k, inferior, /, lateral prolongation 

 of the cranial cartilage; 1, 2, 3, accessory labial cartilages. 



continuous at g, with another bar of cartilage e, which is con- 

 nected with the antero-lateral part of the skull beneath the 



o 



