REPORT ON THE ECHINOIDEA MORTEN SEN 



269 



tem. The primaries usually are of a slight pinkish tint. The spec- 

 imens from station 5512 are darker, but they give very much the 

 appearance that this is due to preservation. 



Notes. — The specimen from station 5348 is young, and its identifica- 

 tion is not quite certain. 



Some of the specimens from station 5512 are infested with a kind of 

 parasitic organism that rests in small circular holes at the base of the 

 oral primary spines. Within these holes there is a rather thick fibrillar 

 sack containing a thick-walled globular cyst. Within the cyst an 

 organism can be seen, but what kind of an organism it is I have been 

 unable to ascertain. 



GONIOCIDARIS (CYRTOCIDARIS) TENUISPINA, var. TUBERCULATA, new variety 



Plate 57, fig. 3; plate 59, fig. 1; plate 61, figs. 9-11; plate 73, figs. 7-8; plate 79, 



figs. 4-8 



Locality. — Station 5219; between Marinduque and Luzon; Mom- 

 pog Island (NE.) bearing N. 35° 30' W., 12.25 miles distant (lat. 13° 

 21' 00" N., long. 122° 18' 45" E.); 969 meters; bottom temperature 

 10.44° C; green mud; April 23, 1908 (22 specimens, and some frag- 

 ments, Cat. Nos. E. 1265, E. 1374, the type, U.S.N.M.). 



Measurements 



Characters. — From the typical form these specimens, and some 

 others from the same locality, differ in the following characters: 



The ambulacra are more closely tuberculated; inside the marginal 

 tubercle each plate carries 2 or 3 tubercles, which are not much 

 smaller than the marginal one and are usually arranged in a fairly 

 distinct transverse series running obliquely upward toward the median 

 line. There is no distinct naked sunken median line, the grooves 

 formed by the horizontal sutures just connecting along the median 

 line. The wall between the pores is flatter than in the typical form. 

 (PL 73, figs 7-8.) 



In the interambulacra the naked median line is narrowed, and 

 correspondingly the number of tubercles on the median part of the 

 plates is rather conspicuously larger; the upper interambulacral plates 

 in general are more closely tuberculated than in the typical form. 



