APPENDIX III 379 



RAMUS (L. branch), a branch or outgrowth; as. the ramus of the mandi- 

 ble; the aortic rami of the amphibia and birds; the ramus com- 

 municans of the peripheral nerves. 



RAPHE (G. rhaphe, a seam), a seam-like appearance of an organ; the 

 median line of the body; the dividing line of the scrotum. 



Ratitae (L. ratitiis, like a raft), a sub-class of birds lacking a carina on 

 the sternum; the non-flying birds including the ostrich, emu, kiwi, 

 etc. 



RECTUM (L. rectus, straight), the lower, enlarged portion of the intestine. 



RENAL (L. rencs, kidneys), pertaining to the kidnej^s; renal corpuscles; 

 renal portal. 



Reptilia (L. reptilis, from repo, to creep), a class of vertebrates, covered 

 with ectodermal scales, including turtles, lizards, snakes, dinosaurs, etc. 



RESPIRATORY (L. re, back, plus spero, to breathe), relating to breathing; ob- 

 taining oxygen from the surrounding medium. 



RETINA (L. rete, a net), the cell laj^er of the eye containing the receptors 

 of light impulses. 



RETRO (L. backward), that which is back or behind another structure; 

 retro-peritoneal. 



RHiNAL (G. rhis, nose), relating to the nose or snout; rhinencephalon ; 

 rhinocoel; rhinitis. 



Rhynchocephalia (G. rhynchos, snout, plus kephale, head), an order of 

 reptiles from New Zealand; the most primitive liA'ing reptiles. 



RoDENTiA (L. rodo, to gnaw), an order of mammals with two gnawing 

 incisors in each jaw; includes rats, beavers, capybara, etc. Rabbits are 

 usually included in a separate order (Lagomorpha) as they have 

 four incisors and other divergent characters. 



ROSTRUM (L. beak), a projecting snout, or any projecting process; spe- 

 cifically, the cartilage supporting the snout of the dogfish. 



Ruminants (L. rumen, throat), an artificial grouping of mammals, in- 

 cluding the herbivorous land mammals which chew a cud. 



SACCULUS (L. diminutive of saccus, a sac), a small, pouch-Hke structure; 



the sacculus of the ear. 

 SACRUM (L. sacrum, from sacer, sacred; the part offered in sacrifice), the 



lower end of the vertebral column, attached to the pelvic girdle; 



sacral, pertaining to the sacrum. 

 SAGITTAL (L. sagitta, an arrow), a median plane along the antero-posterior 



axis; a longitudinal section may be to either side of the median line. 

 Salamandrina (G. salamandra, salamander), a group of urodele am- 

 phibia, including the salamanders which lose their gills in the adult 



stage, and are generally land living. 

 SALIVARY (L. saliva, spit), pertaining to the glands which secrete saliva. 

 Sauropsida (G. sauros, lizard, plus opsis, appearance), a group term which 



includes the reptiles and birds. 

 SAURUS (G. sauros, a lizard), a combining form, referring to lizard, or 



lizard-like; Ichthyosaurs ; Dinosaurs, etc. 

 SCLERA (G. skleros, hard), a combining form, implying that which is 



hard, or which gives rise to hard structures; sclerotic, sclerotome. 

 SCLEROTOME (G. sklcros, hard, plus toma, a cut), that part of the epimere 



which gives rise to the vertebral column and connective tissues. 



