ACANTHOPTERYGII. 119 



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.; Mus. Ad. Fred., 



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



one known. (1) 



CoTTUSj 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, h.', B\. 40. (The Father-Lasher.) Three spines 

 on the preoperculum. 



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

 operculum with four spines, the first very long. 



C. quadricornisyBl., 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 ododecim spinosus, Mitchill, New York, 

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



