ACANTHOPTERYGII. H9 



D. volitans; Trigla volitans, L.; BL, 351, the Mediterranean 

 species, is a foot long; brown above; reddish beneath; fins black, 

 variously marked with blue. 



D. orientalis, Cuv. Russel, 161, is a neighbouring species 

 from the Indian Ocean. 



Cephalacanthus, Lacep, 



Nearly the form, and particularly the head of the Dactylopteri; dif- 

 fering from them, however, in the total absence of supernumerary 

 fins or wings. 



C. spinarella; Gasterosteus spinarella, L.j Mus. Ad. Fred., 



pl.xxxii, f. 5. A very small species from Guiana, and the only 



one known.(l) 



CoTTUs, Lin. 



Head broad, depressed, mailed, and variously armed with spines or 

 tubercles; two dorsals; teeth front of the vomer, but none on the pa- 

 latines; six rays in the branchiae, and only three or four in the ven- 

 trals. The inferior pectoral rays, as in Trachinus, are not branched; 

 few csecal appendages, and no natatory bladder. 



Those that inhabit fresh water have a nearly smooth head, and 

 but one spine to the preoperculum; their first dorsal is very low. 

 The most common species is 



C. gobio, L.; Bl. 39, 1, 2. (The River Bull-head.) A small 

 blackish fish, four or five inches in length. 

 The salt water species are more spinous, and when irritated their 

 head becomes still more inflated. Such are 



C. scorpius, L.; Bl. 40. (The Father-Lasher.) Three spines 

 on the preoperculum. 



C. huhalis, Euphrasen., New Stockh. Mem., VII, 95. Pre- 

 operculum with four spines, the first very long. 



C.quadricornis,B\., 108. (The Four-Horned Bull-head.) Dis- 

 tinguished by four quadrate and bony tubercles. These three 

 species are found in the European seas, the latter more parti- 

 cularly in the Baltic. 



America and the north of the Pacific Ocean produce much 

 larger ones. (2) A small species is taken in the latter, whose 

 singularity of form entitles it to notice: it is the 



C. diceraus. Pall.; Synanceia cervus, Tilesius, Mem. Acad. 



(1) It is from Guiana, and not from India, as has always been asserted. 



(2) C virginianus. Will., X, 15, or ododedm spinosus, Mitchill, New York, 

 Trans., IV, p. 380; — C. polyacanihocephalus. Pall., Zool., Kuss., &.c. 



