198 HANDBOOK OF INVERTEBRATE ZOOLOGY. 



the third maxilliped, into the inner branchial chamber and 

 out from the outer branchial chamber to the opening above 

 the second maxilla where the water is bailed out by the 

 scaphognathite, and swept away from the body in a current 

 which flows forwards, between, and under the maxillipeds. 

 11. Carefully cut away the carapace of a living speci- 

 men in order to expose the gills and heart. Notice the 

 play of the flabella in the branchial chamber, and the 



Fig. 102. 



Pig. 102. — Inside view of posterior portion of "cardiac" pouch of 

 the stomach of Callinectes hastatus. (Drawn from nature by W. K. 

 Brooks. ) 



Explanation of the reference letters in Figs. 101 and 102 : — 

 a. Pterocardiac ossicle, b. Zygocardiac ossicle, c. Pyloric ossicle. 

 d. Urocardiac ossicle, e. Prepyloric ossicle. /. Opening into pyloric 

 pouch, g. Valvular fold over the opening of the oesophagus, h. Zygo- 

 cardiac tooth. i. Bottom of stomach, j. Inferior accessory ossicles. 

 k. Accessory cardiac tooth. I. Superior accessory ossicles, m. Opening 

 of oesophagus, n. CEsophagus. p. Posterior end of stomach, c p. Car- 

 diac pouch. 



rhythmical beating of the heart. Make a small opening 

 through the pericardium, and introducing a few drops of 

 some colored fluid, such as finely-powdered carmine in 

 water, notice the manner in which it is drawn through the 



