ARCHITECTONICID^. 241 



neglecta, C. B. Adams. trilineata, Vhil. 



paupercula, C. B. Adajiis. tubercularis, Mont. 



punctata, Phil. tuberosa, Hinds (Terebra). 



subulata, C. B. Adams. turritella, Quoy. 



terebellum, C. B. Adams. vicina, C. B. Adams. 



terebralis, C. B. Adams. virgulosa, C. B. Adams. 



Sub-gen. aiaba, H. and A. Adams (Rissoa, sp. C. B. Adams). 



Shell smooth, semipellucid, whorls sometimes with a few, 

 irregular varices ; outer lip thin, simple ; aperture slightly 

 emarginate anteriorly. 



melanura, C. B. Adams. trivaricosa, C. B. Adams. 



Fam. ARCHITECTONICID^. 



Tentacles folded, with the suture below ; eyes sessile on 

 the upper surface of their bases. Mantle included ; gill- 

 cavity divided by a longitudinal fold. Foot moderate, 

 formed for walking. 



Operculum horny, spiral, ovate or circular. 



Shell orbicular, more or less depressed and trochiform ; 

 axis widely perforated ; aperture not pearly within. 



The proboscis in this family is retractile, and the 

 tongue, according to the observations of Dr. Gray, is en- 

 tirely unarmed ; the tentacles are laterally folded, and 

 the relations of the animal appear to be more with Tere- 

 bridce and Pi/ramidellidce, than with any other family. 



Genus ARCHITECTONICA, Bolten. 



Operculum ovate, flat, few-whorled. 



Shell conical, last whorl angulated at the periphery, 



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