272 SEMIPHTLLIPIANA. 



. is , intermediate between Aricylus and Patella ; while in the 

 aspect of the beak, the observer is reminded of Navicella. 

 Bkodeeipia, Gray, contains part of this genus typified by S. 

 rosea. PI. xxiv. fig. 508, 509. Scutella crenulata. 



SCUTIBRANCHIATA. Bl. (Scutum, a shield; branckice, gma.) 

 The third order of Paracephalophora Hermaphrodita, Bl, con- 

 taining animals with patelliform, but not symmetrical shells, 

 and divided into the families Otidea and Calyptracea, 



SCUTUM. Montf. (A shield.) Paemophoetjs ELOuaATUS, Lam. 



SECUBIPOEM. (Securis, an axe ; forma, shape.) Hatchet- 

 shaped. Ex. Pedum, fig. 179. 



SEDENTABT ANNELIDES. Lam. The third order of the 

 class Annelides, Lam. distinguished from the other two orders 

 by the circumstance of the animal being enveloped by a shelly 

 tube which it never entirely leaves. The order is divided into 

 the families Dorsalia, Maldania, Serpulacea, and Amphitrites. 

 Eig. 1 to 13. 



.SEA DATE. The common name for Pholas Dactylus in the 

 market, given to it on account of its cylindrical shape. Eig. 35. 



SEGMENTINA. Eleming, 1824. Nautiltis Lacustris, Mon- 

 tagu. Test. Brit. Planorbis nitidus, Drap. tab. 2. Eig. 17 to 19. 



^EMICOEDATE. Half heart-shaped. 



SEMIDISCOIDAL. Eorming the half of a circular disc. 



SEMILUNAE. Half moon-shaped. 



SENECTUS. Humph. A genus of " Senectinse," thus described 

 by Swainson : " Imperforate ; the base produced into a broad 



, flat lobe, spire rather elevated and pointed ; the whorls convex ; 

 aperture perfectly round ; not more oblique than Helix ; inner 

 lip entirely wanting, imperialis. Mart. 180. f. 1790. marmoratus. 

 L M. 448. f. 1." Sw. p. 348, 



SEMIPHYLLIDIANA. Lam. The second family of the order 

 Gasteropoda, Lam. the genera of which are distinguished as 

 follows : — 



1. Umbrella, round, flat ; apex central, muscular impression 



not interrupted. Eig. 232. 



2, Pleuegbeanchtjs, apex lateral, sub-spiral. Eig. 232, 



