EXPLANATION OF PLATES. 



Plate 1. 



Fig. 514. — A young specimen of Uolopus rangii from Cuba attached by a spreading base after the man- 

 ner of a sessile barnacle. (Adapted from P. H. Carpenter.) 

 515. — The topmost columnal in a specimen of Metacnmis rotundus from southwestern Japan. 

 516. — A series of columnals from the center of the column of a species of Platycrinus, illu.strating the 



short spirally an-anged t>pe of columnal derived through the bourgueticrinoid type, viewed 



from the broader side (a), from the narrower side (6), and from the end (c). (Drawing by 



the author.) 

 517.— A fully grown specimen of Holopm rangii from Barbados attached by a thick unjointed column 



after the manner of a stalked barnacle. (Adapted from P. H. Carpenter.) 

 518. — A portion of the dried column of a young pentacrinoid larva of Antedon bifida from England, 



showing the long bourgueticrinoid columnals, and the annulus about the center of each. 



(After W. B. Carpenter.) 

 519. — The twenty -third and twenty-fourth columnals in the stem of a pentacrinoid lar\'a of Hathro- 



metra proliia from East Greenland in which the first brachials have formed, and in which 



the radianal is still present. (After Mortensen.) 

 520. — Columnals from the center of the column of a pentacrinoid larva of Hathromelra sarsii. (Aftet 



Mortensen.) 

 521. — Columnals from the center of the column of a pentacrinoid lar\'a of Antedon petastis. (.\fter 



Mortensen.) 

 522. — Long bourgueticrinoid columnals from about the center of the stem of a fully grown penta- 

 crinoid larv'a of Hathromelra sardi from Norway, in lateral (a) and in end (6) view, (.\fter 



M. Sars.) 

 523. — The upper portion of a columnal from a pentacrinoid larva of Hathrometra prolixa from east 



Greenland, in end (a) and in lateral (b) view. (After Mortensen.) 

 524. — Half of a columnal from a pentacrinoid larva of Hathrometra sarsii from Norway, showing the 



expanded end and the interlocking teeth along tlie fulcral ridge. (After M. Sara. ) 

 525. — The articular face of a columnal of Proisocrimis ruberrimus from about the middle of the 



column, showing the radial crenellse. 

 526. — Columnals from the middle of the stem of the pentacrinoid larva of Heliometra glacialis. (After 



Mortensen.) 



Plate 2. 



Fig. 527. — The column of a specimen of Balhycrinus maximus from the Indian Ocean, showing the pro- 

 gressive variation in the type of the columnals from near the proximal to near the distal 

 end; (a) the distal and (b) the proximal portion. 



528. — Lateral view of a young specimen of Comatilia iridometri/ormis, sliowing the interradials. 

 (Drawing by the author.) 



529. — Ventral view of a young specimen of Comatilia iridometriformii, showing the interradials. 

 (Drawing by the author.) 



530. — The inner ends of the orals of a very young pentacrinoid larva of Hathrometra sarsii from 

 Norway. (After M. Sars.) 



531._Diagrara illustrating tl\e progressive resorption of the dorsal pole of the centnKlorsal, and its 

 effect upon the arrangement of the cirri. (Drawing by the author.) 



383 



