PLATE XXXII. 



Rhynchopygus pacificus, 1-10. 



1. Abactinal part of the test removed, to show the position of the upper part of the diges- 



tive cavity, i", anal part of digestive cavity (intestine proper) ; i"*, diverticuhi of 

 intestine near the actinostome (see Fig. 5). Digestive cavity runs from i"" to j", 

 parallel with the actinal floor (see Fig. 3), turns upon itself at the anterior extremity 

 to i", passes under intestine i' to i'", and leads to anal opening by i". 



2. Shows the position of the four lateral genital branches. 



3. Shows the course of the digestive cavity parallel to the actinal floor (actinal part of 



test removed) the oesophagus widens rapidly at i'', wliich sends out the diverticula 

 (Figs. 1 i*, 5 i<^) to the broad digestive cavity i'i' ; at i" it turns upon itself and opens 

 into the broader stomach i" %" of Fig. 1. A mesentery extends completely across 

 the actinal floor, and is edged by a vessel v. 



4. Section showing in profile the successive course of the digestive cavity i" i" i", the 



position of the ovaries o, and of the stone-canal c. 



5. The interior of the test round the actinostome, showing the phyllodes and the trend of 



the oesophagus leading to the diverticula i'*, wliich is over the odd ambulacral region. 



6. Ambulacral tube from petaloid portion, from above. 



7. Same as Fig. 6 in profile. 

 8, 9, 10. Sucker of phyllodes. 



Metalia sternalis, 11, 13. 



11. Part of test round actinostome showing the large pouch of actinostome running to the 



oesophagus, extending over the odd interambulacral space. 



12. Interior of test round abactinal pole, showing the position of the four ovaries. 



Palaeostoma mirabilis, 13-15. 



13. Seen from above (n. s.), copied from Gray. 



14. Actinostome. 

 1"). Anal pyramid. 



Echiuocardium pennatifidum, IG. 



16. One of the pedunculated amlnilacral suckers rmuul the actinostome. 



Spatangus purpureus, 17, If!. 



17. Abactinal part of test removed, n". anal extremity of alimentary canal ; i i', intestine ; 



i', diverticidura (anus aliove). 



15. Actinal floor removed, a, oesophagus ; i'i", digestive canal ; v, vessel communicating 



from ambulacral system with the water-system ; s, limestone support near actino- 

 stome for support of main mesentery (mouth anterior). 



17, 18 copied from Hoffmann, two thirds natural size. 



(Fiff.'i. 1-4, 11, 12, natural size ; others magnified.) 

 All Figs, not otherwise credited, drawn from nature by A. AGASSIZ. 



