UNIVALVES. 



PLATE XXXI. 



Genus. ANCILLA. 



Character. Shell spiral and acuminate; the mouth ovate, and ending at the 



bottom in an open slant ; the columella having a thickened girdle, which surrounds 



it on the back of the shell, and is slightly or deeply umbilicate in the different 



species. 



Species. 



No. 1 . Ancilla alba. Shell white, and crenated upon each fold of its spire, with 

 slight longitudinal ridges. From Dr. Lettsom's Museum. 



No. 2. Ancilla fasciata. Shell of a warm brown colour, interlined on each fold 

 of the spire with a yellow line ascending ; the girdle white and umbilicate. 



No. 3. Ancilla pallida. Shell painted externally with a rich pattern of pale 

 red, resembling a map ; the girdle thick and projecting ; spire short and sub- 

 turreted. A native of the coasts of New Holland, where it is found in great 

 abundance. 



No. 4. Ancilla fulgens. Shell of a bright yellow colour, shaded with pink ; the 

 girdle very much twisted and umbilicate ; the spire sinuated, and swelling 

 out, forming in the whole a beautiful and splendid appearance. A native 

 of the South Seas. From a specimen in the Author's Museum : fine speci- 

 mens are rather rare. 



No. 5. Ancilla maculata. Shell spotted with a rich coffee colour, resembling 

 in some degree No. 3 in its general form, only more acuminate and rounded 

 in the folds of its spire. Native place not exactly known. 



No. 6. Ancilla ccerulea. Shell of a singular blue colour, striated in its body 

 and spire, and slightly umbilicate. 



No. 7. Ancilla lineata. Shell of a pale red, richly striped across the whole 

 body and spire with red lines ; the maxilla oris richly denticulated at the 

 bottom. 



REMARKS. 



The genus Ancilla has some distant resemblance to the Oliva genus, except that the folds 

 of its spire are not separated by a channel ; it differs from the Buccinum chiefly by the 

 thickened collar upon its base. Several species of this shell have been lately discovered in 

 a fossil or petrified state, in places remote from the sea, but none of them exactly resembling- 

 such as are recent, or at present existing in the sea. They add to the wonderful proofs of 

 analogy which exist through all the parts of nature, and confirm most strongly the idea of 

 the former extension of the ocean, either universally or partially, over the surface of the 

 globe. 



