78 



HAXDBOOK 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 (c?). These are the true radial blood- 

 vessels. 



Pig. £3. 



Fig. 33. — Transverse section of the ambulacral furrow Of the ray of 

 a starfish, magnified about one hundred and fifty diameters. 



a in. Ambulacral plates. r lo. Radiatmg water-tube. m. Ambu- 

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

 partition. I. Thickened band formed by the epith(!lium 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. g. Outer pigmented layer. 



