THE APODOUS HOLOTHUKIANS 177 



Caudina CONTEAGTACAUDA. 



Plate IX, Figs. 9-13. 



Caudina contractacauda Clark (antea, p. 38). 



Length. — 70 mm., of which more than one-third is caudal appendage. 



Color. — Very pale brown. 



Distribution. — Reported only from near the Aleutian Islands (Clark). 



Remarks. — Although undoubtedly near the two preceding species, this form 

 may be readily recognized by the very different calcareous deposits. It may 

 be considered the North Pacific representative of chilensis. 



Caudina californica. 

 Plate X, Fig. 13. 

 Caudina californica Ludwig, 1894, p. 155. Calcareous deposits, pi. xv, figs. 1-6. 



Length. — 98 mm., of which 42 are caudal appendage. 



Color. — Yellowish gray. 



J)iSTEiBUTioN. — Reported only from the vicinity of Lower California, 2,850 

 m. (Ludwig) ; 85 m. (Clark, antea). 



Remarks. — This is a well-marked and perfectly distinct species, of which 

 only the few specimens in the National ]\Iuseum are known. The small speci- 

 men, collected in only 85 m. of water, may belong to a different and hitherto-un- 

 described species, but in view of the very scanty material, it seems wiser to 

 consider it a young californica. The plates in this small specimen are mostly 

 less than half as large as in the type and have only 2-8 holes, which are very 

 large in proportion to the size of the plate. The knobs on the surface of the 

 plate are rounded or blunt, instead of being sharp. The plates are not at all 

 crowded, but lie rather evenly distributed through the skin. 



Caudina planapertura. 



Plate IX, Figs. 6-8. 



Caudina planapertura Clark (antea, p. 37). 



Length. — 67 mm., of which 27 are caudal appendage. 



Color.— Gray with minute light-brown blotches, which are so numerous 

 dorsally as to give a brownish tinge there. 



Distribution.— Reported only from Wellington Island, Chile, 350 m. 



Remarks.— This species is remarkably distinct from any other member of 

 the genus, owing to the smooth, perforated plates, but superficially it closely 

 resembles arenata. 



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