TECTUS. 103 
SUB. (Under.) Used as a prefix to signify nearly. Thusa bivalve 
shell, the valves of which are nearly alike, would be described 
as swb-equivalve. 
SUB-APLYSIACA. Bl. The first family of the order Mono- 
pleurobranchiata, Bl. containing several genera of Mollusca 
without shells, and the genus Pleurobranchus. 
SUB-MYTILA’CEA. BI. The sixth family of Lamellibranchiata, 
Bl. containing the genera Anodon, Unio, and Cardita. 
SUB-OSTRA’CEA. Bl]. The second family of Lamellibranchiata, 
Bl. containing the genera Spondylus, Plicatula, Hinnites, Pecten, 
Pedum, Lima. 
SUB-SPI'RAL. Not sufficiently spiral to form a complete vo- 
lution. 
SU’BULA. Bl. A genus composed of Trerepra Macunata, Auct. 
and other similar species, which are more ventricose than most 
of the Terebree. Fig. 428. 
SU’BULATE. (Subu/a, a kind of bodkin used: by shoemakers.) 
Applied to shells that are long and pointed as Terebra. Fig. 427, 
428. 
SUCCIN’EA. Drap. (Succinwm, amber.) Fam. Colimacea, Lam. 
Limacinea, Bl. Sub-genus. Cochlohydra, Fer. Descr. Ovate, 
rather elongated; aperture large, entire, longitudinal; spire 
short; outer-lip thin, continuous with the thin, sharp-edged 
columella; inner-lip spread over a part of the body whorl. Obs. 
The shells belonging to this genus of partly amphibious mol- 
lusca, are distinguished from Lymnza, by not having a fold in 
the columella. The 8. amphibia, is of a bright amber colour. 
Fig. 265, 266. 
SUL'CATED. (Sulcatus, Lat.) Having grooves or furrows. 
SU’TURE. (Sutura, Lat.) A seam, stitch, joining together. Ap- 
plied particularly to the line which marks the joining of the 
whorls of a spire. 
SYMME’TRICAL. (ovy, syn, similar ; perpov, metron, proportion. ) 
Both sides alike. Hw. Patella, fig. 229. Ammonites. Fig. 
478. 
SYMPHYNOTA. Lea. A genus of Nayades, in which Mr. Lea 
proposed to include such species of the genus Unio, the valves 
of which are connate, or united at the dorsal margin. We be- 
lieve that this distinction as a genus, has been abandoned by 
its author. The fact is, that all the Uniones are Symphynote 
when in a young state. In Unio Alatus, fig. 147, and Dipsas 
plicatus, fig, 142, it will be observed the valves have not sepa- 
rated at the dorsal edge, but are broken lower down. 
TA’PES. Schum, Punuastra, Sow. 
TEC’TUS. Montf. A genus composed of species of Trocuus, 
having elevated, conical spires, and columella notched or trun- 
cated by a spiral fold. 
