Natural History of British Animals. 237 



base, reddish-brown, passing gradually into a light cream colour 

 towards the oral disc ; whole surface striated longitudinally with 

 alternate opaque white, and translucent bluish lines, and marked 

 irregularly with bright reddish-purple spots. These spots are 

 confined to the outer coat, which is easily peeled off. That be- 

 low it is of a pink colour, and is marked with the striae, which 

 shine through the outer coat. Oral disc of an elongated oval 

 form, white, and bearing on its outer margin numerous rather 

 short tentacula, arranged in three or four irregularrows ; tenta- 

 cula shorter than the body, acuminated, white, each marked 

 with a faint streak of brown ; mouth large, oval ; lips white, 

 contracted into folds ; internal surface of the stomach marked 

 with numerous white striae. Base fixed to a thin horny expansion 

 attached to the apertures of various dead shells, such as Tro- 

 chus cinerarius and T. Magus*, and forming, as it were, an 

 extension of the body-whorl of the shell in a spiral form. Over 

 this, the Actinea is spread entirely, and covers also more or less 

 of the shell. Its oral disc is uniformly situated close to the in- 

 ner lip of the horny case. The aperture of the case is accu- 

 rately surrounded by its body, the margins of the opposite sides 

 of which meet, and are closely applied to one another at the 

 middle of the outer lip of the aperture, whence they run upwards 

 towards the old shell, where they generally separate again, leav- 

 ing its apex uncovered. This arrangement will perhaps be bet- 

 ter understood by a reference to the figures, (Figs. 6 & 7, Pi. II.) 

 The horny membrane to which the Actinea is attached, co- 

 vers, for the most part, nearly the whole external surface of the 

 old shell to which it is fixed, and, from the circumference of its 

 aperture, is prolonged into a large hollow expansion, resembling 

 in form, and occupying, relatively to the shell, the place of, a 

 ventricose body-whorl. Its substance is of uniform thickness 

 throughout its whole extent, of a greenish-brown colour, trans- 

 lucent, having both surfaces irregularly wrinkled transversely. 

 In a recent state it is quite flexible, but when dried it is brittle. 

 It takes fire and burns readily, leaving a very small residuum, 

 which does not effervesce with acids. It is insoluble in boiling 

 water and in alcohol, but dissolves slowly in acids, and in solu- 



• Adams found his specimens " surrounding the apertures of deserted 

 shells of Murcx detpectus." 



