Cyan^a. RADIATA. ACALEPHA. 501 



Medusa herais. Mull. Zool. Dan. t. vii — Medusa, Cordincr's Ruins, 

 No. xi.-M. hem. Macartney, Phil. Trans. 1810, 268. t. xv. f. 5. 

 Minute, campanulate, the mouth subpedunculated, with five very short 



arms This species is one of those which are remarkably luminous at night, 



and is very common. 



57. G. octona. — Body round subcorneal, blunt at the summit, 

 and slightly acuminated. 



Flem. Edin. Phil. Jourri. viii. 299 At the Bell Rock. 



About an eighth of an inch in diameter ; margin furnished with eight simi- 

 lar tentacula, equal to the diameter of the body ; oral disc concave, with the 

 central mouth slightly pedunculated. 



Gen. XXII. CYAN/EA— Body hemispherical ; mouth with 

 arms ; margin of the body with tentacula. 



58. C. aurita. — Convex, translucent, with four incurved se- 

 micircular central markings ; mouth with four long crenulated 

 and ciliated arms. 



Medusa aurita, Linn. Syst. 1197- Mull. Zool. Dan. t. lxxvi.— M. cru- 

 ciata, Turt. Brit. Fauna, 139 — M. cruciata and aurita, Stewart's El. 

 i. 399. — Not uncommon. 

 On the dorsal aspect the body is depressedly convex, smooth ; the mar- 

 ginal tentacula are thick at the base, interrupted in the circle by eight glo- 

 bular organs, with two arms, having a perforated middle process with a black 

 point ; the arms do not appear in very young specimens. 



59- Cfusca. — A brown circle in the centre of the dorsal disc, 

 with 16 rays, of the same colour, converging from the circum- 

 ference. 



Urtica marina, Borl. Corn. 256. t. xxv. f. 7- — Medusa fusca, Perm. Brit. 

 Zool. iv. 57- — Shores of Cornwall. 



Convex, the circumference with 16 knobs, the termination of the rays 

 with intermediate crooked fangs between each ; mouth cruciform. 



60. C. purpurea. — A pale purple cross in the centre, with 

 4' incurved semicircular marks, and 16 diverging deep purple 

 rays. 



Borl. Corn. 257. t. xxv. f. 9 — Medusa purpurea, Penn. Brit. Zool. iv. 



57 Common. 



Margin more incurved than the preceding ; rays of the cross pointed ; 

 mouth cruciform, with 4 arms. 



61. C. tuberculata. — A granulated central spot, with 16 di- 

 verging simple rays. 



Borl. Corn. 257- t. xxv. f. 11 M. tuberculata, Pcnn. Brit. Zool. iv. 58. 



— Shores of Cornwall. 

 The margin has two tubercles between each ray. The arms are narrow, 

 and longer than the body. 



62. C. capillata. — Convex, the margin divided into 16 seg- 

 ments. 



