582 GLOSSARY. 



of Vertebrates; in a restricted sense, the row of plates in the cup of 

 Crinoids, which give origin to the arms, and are usually called the " axil- 

 lary radials." 



SCLERENCHYMA (Gr. sJcleros, hard ; and enchuma, tissue). The calcareous 

 tissue of which a coral is composed. 



SCLEROBASIC (Gr. skleros, hard ; basis, pedestal). The coral which is pro- 

 duced by the outer surface of the integument in certain Actinozoa (e.g., 

 Red Coral), and forms a solid axis which is invested by the soft parts of the 

 animal. It is called " foot-secretion " by Mr Dana. 



SCLERODERMTC (Gr. skleros ; and derma, skin). Applied to the corallum which 

 is deposited within the tissues of certain Actinozoa, and is called "tissue- 

 secretion" by Mr Dana. 



SCLEROTIC (Gr. skleros, hard). The outer dense fibrous coat of the eye. 



SCOLECIDA (Gr. skolex, worm). A division of the Annuloida. 



SCUTA (Lat. scutum, a shield). Applied to any shield-like plates; especially 

 to those which are developed in the integument of many Reptiles. 



SELACHIA or SELACHII (Gr. selachos, a cartilaginous fish, probably a shark). 

 The sub-order of Elasmolranchii comprising the Sharks and Dog-fishes. 



SEPIOSTAIRE. The internal shell of the Sepia, commonly known as the 

 "cuttle- bone." 



SEPTA. Partitions. 



SERPENTIFORM. Resembling a serpent in shape. 



SERTULARIDA (Lat. sertiim, a wreath). An order of Hydrozoa. 



SESSILE (Lat. sedo, I sit). Not supported upon a stalk or peduncle ; attached 

 by a base. 



SET.E (Lat. bristles). Bristles or long stiff hairs. 



SETIFEROUS. Supporting bristles. 



SETIGEROUS (=Setiferous). 



SETOSE. Bristly. 



SIGILLARIOIDS (Lat. sigilla, little images). A group of extinct plants of which 

 Sigillaria is the type, so called from the seal-like markings on the bark. 



SILICEOUS (Lat. silex, flint). Composed of flint. 



SINISTRAL (Lat. sinistra, the left hand). Left-handed ; applied to the direc- 

 tion of the spiral in certain shells, which are said to be "reversed." 



SIPHON (Gr. siphon, a tube). Applied to the respiratory tubes in the Mol- 

 lusca ; also to other tubes of different functions. 



SIPHONOPHORA (Gr. siphon ; wadphero, I carry). A division of the Hydrozoa 

 comprising the Oceanic forms (CalycopJwridce and Physophoridce). 



SIPHONOSTOMATA (Gr. siphon ; and stoma, mouth). The division of Gastero- 

 podous Molluscs, in which the aperture of the shell is not "entire," but 

 possesses a notch or tube for the emission of the respiratory siphon. 



SIPHUNCLE (Lat. sipkunculus, a little tube). The tube which connects to- 

 gether the various chambers of the shell of certain Cephalopoda (e.g., the 

 Pearlj r Nautilus). 



SIPUNOULOIDEA (Lat. siphunculus, a little siphon). A class of Anarthropoda 

 (Annulosa). 



SIRENIA (Gr. seiren, a mermaid). The order of Mammalia comprising the 

 Dugongs and Manatees. 



SOLIDUNGULA (Lat. solidus, solid ; ungula, a hoof). The group of Hoofed 

 Quadrupeds comprising the Horse, Ass, and Zebra, in which each foot has 

 only a single solid hoof. Often called Solipedia. 



SOMATIC (Gr. soma, body). Connected with the body. 



SOMITE (Gr. soma). A single segment in the body of an Articulate animal. 



SPERMATOZOA (Gr. sperma, seed ; and zoon, animal). The microscopic fila- 

 ments which form the essential generative element of the male. 



SPICULA (Lat. spiculum, a point). Pointed needle-shaped bodies. 



SPIRACLES (Lat. spiro, I breathe). The breathing-pores, or apertures of the 

 breathing-tubes (tracheae) of Insects. Also the single nostril of the Hag- 

 fishes, the "blow-hole" of Cetaceans, &c. 



SPLANCHNOSKELETON (Gr. splagchna, viscera ; skelelos, dry). The hard struc- 

 tures occasionally developed in connection with the internal organs or viscera. 



