MUSEUM OF COMPARA.TIVE ZOOLOGY. 7 



922 fathoms; one typical specimen. Lat. 41° 29' 45" N., Lon. 65° 47' 10" W. 

 (1880); depth 980 fathoms; one specimen. Lat. 18° 20' 30" N., Lon. 87° 16' 

 40" W. (1880); depth 600 fathoms; one specimen. 



Holothuria arenicola, Semper. 



Habitat. Charles Island, Gallapagos Archipelago (Hassler Exp., 1872). 

 Five specimens. 



Holothuria lubrica, Selenka. 



Habitat. Mazatlan. Two specimens, agreeing in all respects with the descrip- 

 tion of Selenka. The ventral cj'lindrical pedicels are slightly more crowded 

 than the small dorsal, conical papillae. The curved rods of the integument are 

 strongly spinous, especially towards the extremities. 



Holothuria impatiens, Forskaal. 



Habitat. Charles Island and James Island, Gallapagos Archipelago (Hass- 

 ler Exp.). Four specimens. 



Holothuria imitans, Ludwig. 



One specimen i.s cylindrical, and measures 90 mm. in length and 12 to 14 

 mm. in breadth; the other two are more contracted, of an oval form, and have 

 a length of 70 nmi. and a breadth of 25 mm. The color is dark grayish or 

 reddish brown on the back, and lighter on the ventral surface; the pedicels 

 and papillae are light. The anus is surrounded with five small groups of 

 minute papillae. In one of the specimens the ventral pedicels are distinctly 

 arranged in four series, one along each side and two along the odd ambulacrum, 

 each series containing about four pedicels in breadth. The dorsal papillae are 

 minute, smaller than the pedicels, and scattered without order. There are 

 twenty tentacles. 



The tables closely resemble those described by Ludwig, but he has drawn 

 them with the upper part undermost, as I suggested in my report on the 

 Challenger Holothurioidea. Thus, the tables are completely devoid of disks, 

 and their spire carries at its outward end four double teeth. The rounded or 

 truncate inward end of the spire also bears some spines. No other deposits 

 are to be found in the body-wall itself, but the ambulacral appendages are 

 supported by large, slightly flattened rods, which carry a series of prominences 

 along each side ; these prominences are often united with their ends, so that 

 the rods themselves appear to have a series of holes along each side, just as is 

 found in the rods of Holothuria surinamensis, Ludwig. 



Habitat. Panama (Hassler Exp., 1872) ; three specimens. 



