OF THE BRITISH ISLANDS. 103 



very much shorter rays. This peculiarly shaped fin 

 has in some localities won for these species the popular 

 title of " Trigger-fishes." Examples of both of these two 

 varieties are among the desiderata yet needed to complete 

 the collection of British species contained in the Museum of 

 Economic Pisciculture. The curious Trunk-fishes, genus 

 Ostracion, having their bodies encased in a complete cara- 

 pace of variously ornamented tesselated plates, are exotic 

 members of the same family, of which one species (O. quad- 

 ricornis) has been doubtfully alleged to have been taken 

 on one or two occasions off the Cornish coast. 



FAMILY II. — Globe and Sun-Fishes (Gymnodontidcs). 



Body more or less shortened ; the bones of the upper 

 and lower jaws coalescing in such a manner as to form a 

 trenchant beak without any arming teeth ; * no spinous 

 dorsal and no ventral fins ; the second or soft dorsal, 

 caudal and anal fins closely approximate. 



Of the Globe-fishes but one species, Pennant's Globe-fish 

 {Tetrodon longicephalus), No. 192, has been rarely captured 

 on the south coast of England and Ireland. Its chief 

 peculiarity lies in its capacity to distend a considerable 

 area of its skin in the region of the thorax, through the 

 imbibition of air or water, into an almost globular shape, 

 after the manner of a huge crop. The surface thus dis- 

 tended is armed with thickly-set defensive spines, lead- 

 ing the way to the tropical Globe or Porcupine-fishes 

 (Diodon), in which the entire body is beset with formidable 

 spines, and distensible at will into a spheroidal form. The 

 inflated skins of these fish are largely used by the Chinese 

 for the purpose of making ornamental lanterns. Of the 

 species known as Sun-fishes, included in the same family 



