i6 4 



MANUAL OF ZOOLOGY 



SECT. 



It is found by experimenting with this digestive fluid 

 that it has an action on food-matters similar to that 

 exerted by the secretion of the pancreas in the Vertebrata, 



<ad\Ni 



JVtr.R 



T.F 



'.Ratt.Aml.V. 

 * v Rad.BV. 



Her. Eplkm 

 Derm 



FIG. 82. Diagrammatic sections of a Starfish. A, vertical section passing on the 

 right through a radius, on the left through an inter-radius. The off-side of the 

 arr.bulacral groove with the tube-feet (T. F.) and ampullae (AmJ>.) are shown in 

 perspective. B, transverse section through an arm. The ectoderm is coarsely 

 dotted, the nervous system finely dotted, the endoderm radially striated, the 

 mesoderm evenly shaded, the ossicles of the skeleton black, and the coelomic 

 epithelium represented hy a beaded line. A mb. os. ambulacral ossicles ; A mf>. 

 ampullae ; A n. anus ; C. A mb. V, circular ambulacral vessel ; C. B. V. septum 

 of ring blood-vessel ; Cd. CCE. cardiac caeca ; Cce!. coelome ; Cael- Epithin. 

 coelomic epithelium ; Der. Epithm. deric epithelium ; Derm, mesoderm ; 

 Enl. Epthm. enteric epithelium ; Int. cce. intestinal caeca ; Mdpr. madreporite ; 

 Mes. mesentery ; Mth. mouth ; Nv. R. nerve ring ; oc. eye ; os. ossicles of body- 

 wall ; Ovd. oviduct ; Ovy. ovary ; Fed. pedicellariae ; ph. perihaemal spaces ; 

 Pyl. cac. pyloric caeca ; Rad. aib. V. radial ambulacral vessel : Rad. B. V. 

 points to septum in the radial blood-vessel ; Rad. Nv. radial nerve ; Resp. cce. 

 dermal branchiae ; St. stomach ; St. c. stone-canal ; /. tentacle ; T. F. tube-feet. 

 (From Parker's Biology.} 



converting starch into sugar, proteids into peptones, and 

 bringing about the emulsification of fats. From the short 



