ACANTIIOPTERYGIANS. 141 



spine of the ventrals is alone stiff and sharp ; there are six rays in the 

 branchiae, and the abdominal cavity is very short as well as the stomach; 

 they have some cseca, with a natatory bladder which extends into the base 

 of the tail. 



Cep. rubescens, L. ; Lin. Trans. VII, xvii, and Bl. 170, under 



the false name of Cep. tcenia^, the Ribband, or Red-band Fish. A 



Mediterranean species of a reddish colour. 



LoPHoTES, Giorfia, 



Have the head surmounted with a high osseous crest ; to its summit a 

 long and stout spine is articulated, bordered behind with a membrane, and 

 originating from this spine a low fin, whose rays are nearly all simple, ex- 

 tending equally to the point of the tail, which has a distinct but very small 

 caudal; an extremely short anal beneath that point; moderate pectorals, 

 beneath which are scarcely perceptible ventrals, composed of four or five 

 excessively small rays. The teeth are pointed and not crowded; the 

 mouth is directed upwards, and the eye very large. There are six rays in 

 the branchia;, and the abdominal cavity occupies nearly the whole length 

 of the body. 



L. cepedianus, Giorna, Mem. of the Imp. Acad, of Turin, 1805, 

 1808, p. 19, pi. 2. The only species known; it is found, though 

 rarely, in the Mediterranean, and becomes very large f. 



A Ninth Family of Acanthopterygians, 



FAMILY IX. 



THEUTYES. 



The Theutides is as closely allied to the Scomberoides as the preced- 

 ing one, and in other points, such as the armature, which is found in 

 several genera on the sides of the tail, or in others, the horizontal spine 

 before the dorsal, &c. It contains but very few genera; they are all 

 foreign, and have a compressed, oblong body, a small mouth, but slightly 

 or not at all protractile, each jaw of which is armed with a single range of 

 trenchant teeth ; palate and tongue without teeth, and a single dorsal. 

 They are herbivorous fishes, feeding on fucus and other marine plants ; 

 their intestines are very large. 



SiGANUs, Forsk. — BuRo, Commer. — Centrogaster, Houttuyn. 

 — Ampiiacanthus, Block, 



The Sidjans have a remarkable character — unique, in icthyology — in 

 their ventrals, which are furnished with two spinous rays, one external, 



* Add, the Cepola ja-ponica, Krusenst, Voy. pi. Ix, f. i. 



t Tlie description of Giorna is imperfect, because he only had a mutilated speci- 

 men, of whose origin he was ignorant. I drew mine from an individual more than 

 four feet in length, takeu at Genoa. See An. Mus. XX, xvii. 



