MURICID^. 117 



Shell when young free, resembling Rapana ; when adult, some- 

 times with more or less irregular solid shelly extensions of the 

 outer and inner lips, which clasp the axis of coral or the surface 

 of neighboring shells, and at length close the mouth with the 

 exception of the anterior siphonal canal which is converted into 

 a shell}'' tube. No operculum (?). 



We do not know how many of the species allied to the type 

 of the genus may partake of this singular mode of growth ; it 

 has only been observed in B. antipathicus (xliv, 33, 34). A large 

 number of species have been grouped by Messrs. H. and A. 

 Adams in a subgenus GoraUiophila., the character of which is, 

 that thej^ do not (are not known to) form this shelly enclosure. 

 If this supposed difference of habit should be proved b}^ obser- 

 vation, there can be no doubt that the two groups should be 

 generically separated. It may be remarked that no lingual 

 denticles have been found in the animals of Coralliophila, Lepto- 

 conchus or Magilus examined by Troschel. Coralliophila 

 possesses an operculum ; I do not know whether the younger 

 stage of Rhizochilus has one or not, but the presumption is that 

 it has not. 



CORALLIOPHILA, H. and A. Ad. (See remarks above.) A large 

 number of specific forms have been described, many of which 

 have not been figured. Judging from the extreme variability 

 of the well-known species both in form and sculpture, it may be 

 anticipated that most of the more recently characterized species 

 will prove to be s^aionyms. R. neritoidea (xlv, 49). 



GALEROPSis, Hupe. I Venture to place under this name the 

 BhizocMlus madreporarum^ Sowb. (xliv, 35), which possesses 

 differential characters from both Rhizochilus and Coralliophila. 

 The young shell is free, and not unlike a Coralliophila, and in 

 this stage it has a small, thin operculum with lateral nucleus. 

 The animal has a short siphon which scarcely projects beyond 

 the canal. It is sluggish in its movements. As it matures it 

 becomes attached to the coral, on which it lies and adheres with 

 great tenacity, often allowing the foot to be torn away before 

 releasing its hold. The conformation of the lip corresponds 

 exactly with the irregularities of the place of adhesion. Upon 

 removing the animal, scars will be noticed on the coral, more or 

 less worn by the abrasion of the shell, and old specimens will be 

 found to have deposited a shelly base. When removed, the 

 animal is very timid and never wholly expands. It can only 

 partly withdraw behind the columella-shelf, leaving a portion of 

 the mantle and foot exposed. The foot is small, of an oval form, 

 thick and fleshy. The tentacles rapidly taper to a fine point, on 

 which the eyes are sessile a little beyond the middle of their 

 length. The foot is tinged with pale orange, dotted with white 

 along the upper margins. The mantle is colorless centrally, 



