78 HANDBOOK OF INVERTEBRATE ZOOLOGY. 



5. In the partition (k) which divides the peri-haemal 

 chamber into two, notice the cut ends of two or three 

 irregular tubes (cZ). These are the true radial blood- 

 vessels. 



FIG. 3. 



FIG. 33. Transverse section of the ambulacra! furrow of the ray of 

 a starfish, magnified about one hundred arid fifty diameters. 



a in. Ambulacral plates. r w. Radiating water-tube. m. Ambu- 

 lacral muscle, c. Radiating peri-haemal canal, k. Its median vertical 

 partition. I. Thickened band formed by the epithelium of its floor; 

 the nerve, according to Lange. d. Radiating blood-vessels. /. Inner 

 fibrous layer of the surface epithelium; the nerve, according to Lud- 

 wig. fj. Outer pigmented layer. 



