189 Ret 



Retinal. — Pertaining to the retina. (L. retina.) 



Retinaculum. — Horny movable scales with which 

 the spicula are furnished, serving instead of 

 muscles to prevent it being darted out too far. 

 (L. a stay ; from retino, to hold back, and 

 aculeus, a sting.) 



Retinula. — Elongate nerve-cells in the structure of 

 the eye. (L. retina.) 



Retracted (retracti(m).~iB.ead.) When it is con- 

 cealed as far as the brow within the thorax. 

 (L. re, traho, tractum, to draw back.) 



Retractile. — Capable of being produced and with- 

 drawn. (L. retractmn.) 



Retractile.^ — (Head.) When a concealed head can 

 be pushed forwards at the will of the insect. 

 (L. re, and traho, to draw.) 



Retractores ventriculi. — The delicate retractor 

 muscles which assist in supporting the alimen- 

 tary canal. (L.) 



Retractum. — (Head.) [See Retracted.] 



Retro. — A Latin prefix signifying backwards. 



Retrorsum. — (Direction.) Backwards ; in a back- 

 ward direction. (L.) 



Retrose. — Backward ; in a backward direction. 

 (L. retro.) 



Retuse. — Possessing blunt impressions, as if beaten 

 into the surface. (L. re, and from tundo, 

 tusum, to beat.) 



