22 MARINE AND FRESHWATER FISHES 



head armed with projecting spines, the dentition feeble ; 

 branchiostegal rays six or seven in number; air-bladder 

 present or absent. 



Two genera only, each represented by but a single species, 

 are found in the British waters. In the one form, known as 

 the Armed-Gurnard {Peristethus cataphractum), No. 60, the 

 similarity to an ordinary Gurnard is very great, a certain 

 number of the pectoral fin rays being in a like manner 

 freely detached and subserving as ambulatory organs. 

 This species, while moderately abundant in the Mediter- 

 ranean where it grows to a length of two feet, is ex- 

 ceedingly rare on the British coast ; the example on view 

 in the Day Collection was presented to the exhibitor by 

 Dr. Hubrecht of the Leyden Museum. The second type, 

 or Armed-Bullhead (Agonns cataphr actus), No. 29, is 

 a small species rarely exceeding a length of six inches, and 

 is very plentiful on the shallow, sandy shores around our 

 coasts. But for its mail-clad body it might be easily 

 mistaken for one of the ordinary Bullheads, it being 

 destitute of the free, leg-like pectoral rays that characterise 

 the preceding form. Among the exotic members of the 

 CatapJiracti are included the remarkable Flying Gurnards, 

 in which the pectoral fins are so abnormally developed 

 that the fish are enabled by their aid to take short flights, 

 or more correctly long leaps, above the surface of the 

 water. These Flying Gurnards, referable to the genus 

 Dactylopterus, exclusively inhabit the Indian Ocean and 

 other tropical waters, it being another Flying-fish (Exocetus 

 volitans), which more nearly resembles a Herring, that is 

 met with in temperate latitudes. 



