•8 



SYSTEMATIC ARRANGEMENT 



a. Cancellated. 



1. S. cancellata, a" Orb., in Sagra, Cuba, 1846, t. 23. f. 7, 9. 



b. Smooth. 



2. S. microscopica, (Stmtliiolaria m.) Gray, Beecheys Voy. 



The foot of Sinusigera Huxleyi is destitute of a float, with a very 

 thin, small operculum. Mantle with a short respiratory siphon. 

 The branchiae are of two kinds, covered and naked ; the covered gill 

 is single, but of considerable length, beautifully pectinated and fringed 

 with long cilia. The naked gills are four in number, similar in cha- 

 racter to those of Macgillivrayia. Each gill is oval or elongated, with 

 a thin, frilled and corrugated border, beset with long whip-like cilia. 

 The lingual strap with central and lateral teeth, and two file-like 

 triturating plates. Tentacles two on each side. — Macdonald, Proc. 

 Roy. Soc. vii. 193, 1854. 



Sinusigera was arranged by d'Orbigny (Moll. Cuba, 149) near 

 Nassa, on account of its thickened outer lip. It is distinguished from 

 the other Buccinidce by the ringent mouth and three well-marked 

 sinuses separated by prominent lobes. It was first described as a 

 Struthiolaria by me from a specimen in the Paris Museum. 



B. Cochlea. Mantle enclosed in the shell (p. 68). 



a. Phaneropneumona. Gills vascular, branched, on the inner surface 

 of the mantle. Terrestrial. 

 These differ from Pulmonata in the mantle being free from the 

 nape, leaving the pulmonary cavity open. Animal unisexual. Oper- 

 culum distinct, spiral, or annulated. 



Fam. VI. CYCLOPHORID.E. 



Gills vascular, branched. Shell free, conic. Mouth roundish or 

 Fig. 46.— Teeth of Cyclophorus Tuba. 



ovate. Eyes sessile, on the outer side of the base of the tentacles. 

 Operculum spiral. 

 Terrestrial. 



