208 ANTIIOZOA IIELIAXTHOIDA. 



Bay : — to Bulla lignaria as well as the larger Trochi it is oc- 

 casionally found attached." W. Thompson. 



" This beautiful species is longitudinally sulcated, having the 

 edges of the base crenated : the lower part is an obscure red, and 

 the upper part is transparent white marked with fine purple spots ; 

 the outer circumference of the aperture has a narrow stripe of pink. 

 When expanded, the superior division of the body seems formed of 

 fleshy bars placed in a reticulated manner, and lined with a fine 

 membrane. From perforated warts, placed without order on the 

 outer coat, issued white filamentose substances variously twisted 

 together. I have observed a similar body ejected from the mouths 

 of all the species of this genus which have fallen within my no- 

 tice." — Adams. 



The following more detailed description of this very interesting 

 species is by Dr. Coldstream : — " General mass of the animal flat- 

 tened and extended ; thickness at the oral disc three-tenths of an 

 inch, diminishing towards the circumference of the base ; longest 

 diameter of the base about three inches ; margin minutely crenated ; 

 colour of the body, near the 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 below 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 nume- 

 rous rather short tentacula arranged in three or four irregular rows : 

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

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

 tracted into folds ; internal surface of the stomach marked with 

 numerous white stride. Base fixed to a thin horny expansion at- 

 tached to the apertures of various dead shells, such as Trochus cine- 

 rarius and T. Magus, and forming, as it were, an extension of the 

 body-whorl of the shell in a spiral form. Over this, the Actinia is 

 spread entirely, and covers also more or less of the shell. Its oral 

 disc is uniformly situated close to the inner lips of the horny case. 

 The aperture of the case is accurately 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 sepa- 

 rate again, leaving its apex uncovered." " The horny membrane 



