FISHES. 



211 



Perliaps the fishes most nearly allied to the Chretodontoiclea are two families that 

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

 are the Teutliididie and the Siganidae. These Teuthidoidea are Kshes distinguished 

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

 back, intervening between the s])ines, and limiting their erection forwards. 



The Teuthidid-E comprise those fishes which have the soft portion as long as, or 

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

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





Fig. 120.— Teuthls cmmlcm, binbr 



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 deprcssible in, or erectile from, a 

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

 appendages noticed are quite efficient 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 



