ASTRALIUM. 241 



concave below; operculum oblong, nucleus nearly on the margin, 

 subterminal, outer face with two strong ribs. 



Panamic and Californian Provinces, 

 Cariiildea Swains., in part, is a synonym. 



A. OLivACEUM Wood. PI. 53, figs. 39, 40. 



Shell conic, acute, imperforate, olive-green or brownish ; whorls 

 6-7, slightly convex, obliquely finely striate, longitudinally finely 

 plicate, the folds at right angles to the striaj, and interrupted one- 

 third of the distance from the suture to the periphery by two spiral 

 impressed furrows; suture undulating, linear; peripheral carina 

 slightly nodose; l>ase concave, radiateiy finely lamellose striate, 

 with a somewhat nodulose rib revolving midway between the pe- 

 riphery and the center; aperture silvery white within, oblique, angled 

 and channelled at outer side; base nearly straight; columella arched, 

 deeply excavated at position of umliilicus, the whole umbilical area 

 brilliant vermillion, with a black sj^iral rib. Alt. 55, diam. 65 mill. 



Central America to Gidf of California. 



Operculum (pi. 59, figs. 24, 25) oval, black to yellowish inside, 

 with marginal apex, frequently concealed by growth of the last 

 whorl; outside white, strongly bicostate. T. erythropthalmvs Phil, 

 and T. brevispinosus Val. are synonyms. 



A. BuscHii Phil., 1844. PI. 53, figs. 37, 3cS. 



Shell conic, imperforate, solid, olivaceous brown, maculated ob- 

 scurely above with brown, green or white; whorls 7, longitudinally 

 costate below the sutures and above the j)eriphery, with two spiral 

 series of tubercles around the middle of the flattened upper surface, 

 or sometimes finely irregularly plicate over the whole upper surface; 

 periphery acutely carinated, bearing numerous short compressed 

 triangular radiating spines ; base flat, densely radiateiy lamellose- 

 striate, with a strong rib revolving midway between periphery and 

 center; aperture oblique, pearly white within, ti-ansversely ovate, 

 deej^ly channelled at periphery ; columellar region white, strongly 

 bicostate, deeply excavated at position of umbilicus ; parietal callus 

 not much extended. Alt. 30-40, diam. 40-50 mill. 



Panama to the Gulf of California. 



Operculum (pi. 59, fig. 27) oblong, nucleus submarginal ; outside 

 white, with a strong curved central rib, its terminations joined by 

 a A-shaped ridge. 

 16 



