230 MARINE INVERTEBRATES 
ger.op 
BS 058 
> rag 958 OSS 
7t.bl.ves 
Internal organs of a Holothurian, as seen when the body-wall is divided along the middle of 
the dorsal surface: b.w., body-wall; circ. mus., circular layer of muscle; cl., cloaca; cl. op., cloacal 
opening with five teeth ; cuv. org., Cuvierian organs; gen. ap., genital aperture; gen. du., genital 
duct; gen. gl., genital gland; int., intestine; inter. oss., interambulacral ossicles; int. ves., in- 
testinal vessels; long. mus., longitudinal band of muscle; mad. can., madreporic canals; mes., 
mesentery ; pol. ves., Polian vesicles ; rad. amb., radial ambulacral vessel ; ri. bl. ves., ring blood- 
vessel; resp., respiratory trees; ring-ves., ring-vessel of the ambulacral system ; stom., stomach. 
