FISHES. 



211 



Perhaps the fishes most nearly allied to the Chaetodontoidea are two families that 

 have been associated together under the super-family name TEUTHIDOIDEA ; these 

 are the Teuthididse and the Siganidte. These Teuthidoidea are fishes distinguished 

 by the development of transversely expanded, buckler-like, subcutaneous plates on the 

 back, intervening between the spines, and limiting their erection foi'wards. 



The TetjthididjE comprise those fishes which have the soft portion as long as, or 

 longer than, the spinous, only the usual external spines to the ventrals, and the head 

 considerably produced in front of the eyes. When adult, all are armed with spines 





Fig. 120.— Teuthis coeruleus, barber-fish, surgeon. 



or sharp ridges on the sides of the tail. The most characteristic have only one on 

 each side, which is lancet-like, hooks forward, and is depressible in, or erectile from, a 

 groove. They have received the names barber-fish, surgeon, and doctor. The 

 appendages noticed are quite efiicient weapons, and are vigorously used by the animal 

 for offence as well as defence. If an intruder or enemy approaches too near the 

 acanthurous tenant of a favorite spot or corner, he is met by a vigorous slash of the 

 tail, with erected lancets, which may inflict a serious wound. In fact, all the species 



