259 



Plate XIX. 



Fig. 1. Ophiopluteus of Ophiothrix species a, Misaki, 17/VI. 14. ''"/i- 



2. — — — c. Jolo, 20/III. 14. "o/i. 



3. — — — b. Taboga, Panama. XII. 1915. «7i. 



4. - — — _ _ ■ __ 28/^. 



5. - _____ _ _ _ 43/^. 



6. — — — The young Ophiurid has been developed and 

 dropped off, the posterolateral arms remaining in connection and still continuing 

 the pelagic life. Tobago, Panama. XII. 1915. "/i. 



7. Ophiopluteus of Ophiothrix, species d. Somewhat restored, especially the intestinal 

 tractus. Off Jolo. 20/III. 14. ^Vi. 



Plate XX. 



Fig. 1. Larva of Ophiothrix angulata Say, var. poecila H. L. Clark. Drawn from life. 40 

 hours old. a"7i. 



2. Same, 4^/^ days old. Drawn from life, ^''"/i- 



3. Ophiopluteus opulentus, species c. The young Ophiurid has been developed and 

 dropped off, the posterolateral arms remaining in connection and continuing pelagic 

 life. The arms are not represented in full length, ought to be ca. 4 cm longer by 

 this magnification. The small swelling in the middle to be noticed, ^^/j. 



4. Same as fig. 3, showing beginning regeneration of the larval body. *Vi- 



5. Same specimen as fig. 4, more magnified. Showing beginning formation of mouth. 



Plate XXI. 



Fig. 1. Ophiopluteus costatus, species a. '"/i. 



2. — — — b. «»/!. 



3. — opulentus, species a. Slightly restored. *^/i. 



Plate XXII. 



Fig. 1. Ophiopluteus retrospinus, species a. The nervous system is distinctly seen. ^Vi- 



2. — — — b. Nervous system only partly distinct, ""/j. 



3. — opulentus, — c. ^f^. 



Plate XXIII. 



Fig. 1. Ophiopluteus fulcitus, species a. ^'/i. 



2. — _ _ b. "Vi- 



3. — __ _ c. "Vi- 



Plate XXIV. 



Fig. 1. Ophiopluteus fulcitus, species a. i^^/j. 



2. — undulatus, species c. '"/i. 



3. — — — a; in metamorphosis. ^Vi- 



The details of the skeletal plates of the young Ophiurid could not be given quite 

 accurately by this magnification. The first ventral plate has appeared; in four of 

 the interradii is seen an unpaired plate, which evidently represents the mouth- 

 shield. The preoral band was not very distinct and is perhaps not quite correctly 

 represented. 



Plate XXV. 

 Fig. 1. Ophiopluteus undulatus, species a. Slightly restored. '%. 



2. — — — b. Slightly restored, '"/j. The three inner arm- 



pairs probably still longer than represented. The widening on the ends not distinct, 

 drawn only from analogy with the other species of this type. The shape of the 

 preoral band perhaps not quite correct; the sinuation distinct only on one side. 



33* 



