OF MOLLUSCA. 127 



half-circle ; each contains from six to eight eggs in an advanced 

 stage of development, enclosing young animals which had already v. 



commenced forming their shell. The shell of the young animal, \ 



before it escapes from the egg, appears to be helicoid and reversed, \ 



thus showing some affinity, Mr. Stimpson thinks, with Pyrami- 

 dellidce. — Shells of New England, 38, 1851. 



3. Spiroglyphus. 



Operculum large, circular, convex externally, black, smooth, of \ 



numerous very close-pressed whorls ; scar central, circular. Shell 

 partly sunk into the surface of the shells to which they live attached. 



1. S. corrodens, oVOrb. Cuba, t. 18. f. 1, 3. 



4. BlVONIA. 



Operculum rudimentary, small (spiral). — Adams, Gen. Moll. t. 39. 

 f. 1 a. 



1. B. glomerata, t. 58. f. 4 ; Adams, Gen. Moll. t. 39. f. 1. 



2. B. triquetra, t. 58. f. 5. 



3. B. semisurrecta, t. 58. f. 1. 



4. B. subcancellata, Philippi, t. 58. f. 3. 



5. Serpuloides. 



Operculum none. Foot truncate, radiated at the tip ; front of 

 foot produced into tentacula. 



1 . S. arenaria, t. 57. f. 2, t. 58. f. 6 ; Adams, Gen. Moll. t. 39. f. 2. 



2. S. inoperculata, t. 57. f. 1. 



3. S. dentifera, t. 56. f. 8. 



4. S. varians, t. 128. f. 1. 



Serpuloides varians lives at the bottom of pools on the rocks near 

 Rio, which are only replenished at the highest tides, where the water 

 is concentrated by the evaporation of a high temperature. The 

 animal was generally expanded and agile, and at the least movement 

 of the water it retreated into the bottom of its shell ; when wounded 

 it emitted a deep violet liquor. 



6. Lementina. 



Operculum none. Foot truncate, circular at top. 



1 . L. Cuvieri, t. 57. f. 3 (probably only a badly described and figured 

 Serpuloides arenarius). 



7. Cladopoda. 



Operculum none. Foot elongate, front end simple, hinder ex- 

 tremity oblong, clavate or subtruncate. 



1. C. grandis, t. 56. f. 9 ; Adams, Gen. Moll. t. 39. f. 3. 



2. C. elegans, t. 56. f. 4. 



3. C. nova zealandica, Quoy, t. 56. f. 6. 



