are three in the Sea-lamprey, of which the middle one is joined to the palate by an intermediate smaller one;
Fig. 30.—Upper (A) and side (B) views, and vertical section (C) of the skull of
Petromyzon marinus.
a, Notochord; b, Basis cranii; c, Inferior, and d, Lateral process of basis; e, Auditory capsule; f, Subocular arch; g, Stylohyal process; h, Olfactory capsule; i, Ethmo-vomerine plate; k, Palato-pterygoid portion of subocular arch; l-n, Accessory labial or rostral cartilages; with o, appendage; p, lingual cartilage; q, neural arches; r, Branchial skeleton; s, Blind termination of the nasal duct between the notochord and œsophagus.
the foremost is ring-like, tooth-bearing, emitting on each side a styliform process. The lingual cartilage is large in all Cyclostomes.
