1. FTSTULARIA. 531 



intcropcrculum is exceedingly long and narrow, hidden below tln^ 

 iira;operculuni and tympanic. Tlic gill-opening is wide, closed above 

 the operculum ; the gill- membranes are only slightly united at the 

 base of the urohyal. Five slender branchiostegals : the first (nearest 

 to the subopercle) is divided into two branches, so that one might 

 easily take it for two branchiostegals ; they arc, however, united at 

 the base. Four gills, with a wide slit behind the fourth ; pscudo- 

 branchiiB weU-dcvcloped. The arcus branchiales have no internal 

 rakers; the lower pharj-ngcals are very narrow, provided with a 

 long series of villiform teeth ; a sciies of three elongate patches of 

 similar teeth on each side of the roof of the pharynx. The glosso- 

 hyal is exceedingly elongate, half as long as the tube. 



The bony shields which protect the anterior portion of the trunk, 

 and arc situated immediately below the skin, will be better describ(>d 

 with the skeleton. This portion of the trunk has the muscles much 

 less developed than the posterior ; the shields are the following: — 



1. A narrow strip along the median line. 



2. A pair of broader ones occupying the sides of the back. 



3. A narrow one on the side. 



4. The pubic bones on the belly. 



The ventral fins are situated on the muscular portion of the trunk, 

 and a strip of bony, necdlc-liko ossifications, imbedded in the skin, 

 runs from each fin to the pubic shield, being continued posteriorly 

 along the Avhole length of the side of the abdomen nearly to the 

 caudal fin. The body is much depressed, broader than high, and 

 gradually tapcnng posteriorly ; it is naked ; the lateral line is marked 

 by pores and by small, narrow, bony shields, which are sunk in the 

 skin anteriorly, and become broader and more ])rojecting on the t;dl, 

 where they form a sort of scrrature. The lateral line commences in 

 the scapulary region, is curved towards the median line of the back. 

 running along the Avhole length of the dorsal shield, and then bent 

 downwards, proceeding along the middle of the*sidc. The vent is 

 situated immediately before the anal fin. 



The pectoral fin has an obliciuely curved base and a rounded mar- 

 gin ; it is scarcely longer than the bony orbit, and all its rays are 

 simple ; there is a small foramen posteriorly in its axil. The ven- 

 tral fin is much shorter than the pectoral, and composed of six soft 

 rays, the outer being the longest, simple, and articidated towards its 

 extremity. Both fins are widely apart from each other, and theii- 

 distance from the pectoral is one-third of that from the caudal. 

 The doisal fin is much higher than long, and composed of sim])ie and 

 iinarticidated compressed rays, the sixth of which is the longest ; 

 the posterior rays decrease rapidly in length ; the fin is opposite to the 

 anal, and its distance from the caudal fin is one-fourth of that from 

 the occiput. Anal fin veiy similar to the dorsal. The caudal fin is 

 deeply forked ; its two middle rays are produced into one exceedingly 

 long filament ; sometimes they arc disconnected from each other, 

 forming two filaments ; the upper and lower rays are simply forked. 



The coloiu' of the upper parts is reddish-brown, variegated with 

 numerous blue spots on the sides and on tlic back. 



2m 2 



