The Skeleton of the Fish 



modified persisted tlirougli life, the vertebr^E being strung upon 

 it spool fashion in various stages of development. In the Cyclo- 

 stomi (lampreys and hagfishes) the limbs and lower jaw are 

 still wanting, but a distinct skull is developed. The notochord 

 is still present, but its anterior pointed end is wedged into 

 the base of a cranial capsule, partly membranous, partly car- 

 tilaginous. There is no trace of segmentation in the notochord 

 itself in these or any other fishes, but neutral arches are fore- 



FiG. 42. — Hyostylic skull of ChilosajUium indinim, a Scyliorhinoid Shark. (After 



Parker and Haswell.) 



shadowed in a series of cartilages on each side of the spinal 

 chord. The top of the head is protected by broad plates. 



Fig. 43. Pj^ 4_t_ 



I' IG. 43.— Skull (if ncplranchius indicus (GiiieUn), a notidancid shark. (.\fter 



Parker and Haswell.) 

 Pig. 44.— Basal bones of pectoral fni of Monkfish, S'jualina. (After Zittel ) 



There are ring-hke cartilages supporting the mouth and other 

 cartilages in connection with the tongue and gill structures 



