SCI^ENID^E. 149 



Fourth group Acanthopterygii Sciseniformes. 



Muciferous system on the head well developed. The soft dorsal usually much 

 more developed than the spinous, or than the anal. No pectoral filaments. 



Family, XV SCItENIDJE, Cuvier. 



Branchiostegals seven : pseudobranchiae sometimes concealed or even absent. 

 Body somewhat compressed and rather elongate. Eyes lateral, of moderate or 

 small size. Mouth in front of or below the snout. Cheeks unarmed : preopercle 

 without any osseous articulation with the suborbital ring- of bones ; opercles some- 

 times with weak spines. Barbels present in a few genera. Muciferous system on 

 the head well developed. Teeth in villiform bands, the outer or the inner row of 

 which are often enlarged : canines present in some genera, but neither cutting 

 nor molar-form ones in the jaws: palate edentulous. Two dorsal fins, the spines 

 (8-12) of the first usually feeble, the second much more developed (22-43 rays) 

 than the first: anal with one or two spines and much fewer (5-18) rays than the 

 second dorsal: pectoral rays branched and without free filaments: ventral 

 thoracic with one spine and five rays. Scales ctenoid or cycloid, covering the 

 head and snout, placed in oblique and often sinuous rows on the body. Lateral- 

 line complete, often continued on to the caudal fin. Stomach ccecal. Air-bladder, 

 when present, as a rule with branching or elongated appendages. Pyloric 

 appendages usually few. 



In tropical countries, where these fishes are extensively distributed, the rays 

 pertaining to the second dorsal fin are found to be liable to great variation in 

 number, while the caudal becomes more obtuse as the adult stage is arrived at. 

 The scales are placed in oblique rows, and the number along the lateral-line rarely 

 corresponds with what exists in the row above or that below fit. The eye, 

 likewise, is comparatively much smaller in adults than in the young. 



Uses. The air-bladders of many of these fishes are extensively collected along 

 the coasts of India as they afford a rough isinglass which meets with a ready sale 

 in China. As food their flesh has always appeared to me as tasteless when young, 

 coarse when old. 



As regards classification Bleeker (Mem. stir les Scienoides, 1874) has 

 questioned the utility of separating the genus Scicena from the genus Umbrina 

 merely because the latter possesses a short central barbel beneath the symphysis 

 of the lower jaw. In a few Asiatic forms a rudimentary barbel is found in some 

 examples of Scicena, while the dentition forms a truer guide than the size and 

 length of the second anal spine. The two accepted British genera are Scicena, 

 without a barbel under the chin, and Umbrina, with a barbel at that place, but 

 believing the latter genus has been recorded due to an error, I have omitted it. 



Geographical distribution. The fishes of this family, some of which attain to 

 a large size, are extensively distributed in the tropical and contiguous portions of' 

 the Atlantic, Indian, and North Pacific Oceans, extending into the sub-tropical 

 parts. They are also found in the Mediterranean, and wanderers are sometimes 

 taken on the south coast of Great Britain, or even further north. Some are 

 spread through the fresh waters of the United States. They are almost absent 

 from the Pacific Ocean : none have been recorded from Polynesia, and merely 

 two or three from Australia. In the clear waters of the Red Sea they are 

 unknown, but abound along the coasts of India, especially wherever there are 

 estuaries or the openings of rivers. They pass up tidal waters even to far above 

 where they have ceased to be brackish, and this they do in order to prey on their 

 weaker neighbours. They prefer muddy bottoms to clear water, and where 

 marine siluroids abound in the tropics Sciamoids are rarely far off. 



