328 HAWAIIAN AND OTHER PACIFIC ECHINI. 



and on the same horizontal line are three or four secondaries, while on the ambula- 

 cral side are a pair or two pairs of similar tubercles. One or more of these 

 secondaries are nearly or quite as large as the primary and none are very small, 

 but each plate also carries about twenty miliaries. The areola of the primary 

 tubercle occupies one half or more of the height of the plate. In the ambulacra, 

 each plate has a primary tubercle close to the poriferous area, two secondaries 

 little smaller on the inner half, and six to eight miliaries, of which two are in 

 the poriferous area. The areola of the primary occupies nearly or quite the 

 full height of the plate, particularly below the ambitus, but in large specimens 

 even far above it. The ambulacra are .80-.90 of the interambulacra, in width 

 at the ambitus, while each poriferous area is about .45 of the interporiferous. 

 The genital plates are of moderate size, approximately equal, with the pores 

 in the distal ends; the pores are often so large as to encroach on the coronal 

 plates, cutting clear through the margin of the genital. The oculars are small 

 and all are broadly exsert. The periproct is relatively rather large and is covered 

 with numerous small plates. The entire abactinal system is completely covered 

 with small tubercles. The actinostomal membrane is thin and bare, as usual in 

 the family. The buccal plates are small, and though the two of a pair are near 

 together, the pairs are widely separated. The spines are as usual short and 

 rather stout. The primaries taper slightly or not at all and are truncate at the 

 tip; many of the secondaries are distinctly swollen distally. The pedicellarise 

 and spicules show nothing of interest. 



Although this species is similar to griseus in the form of the test, the much 

 stouter and coarser appearance distinguish it easily. The coloration appears 

 to be different also. The bare tests of the largest specimens are yellowish, the 

 poriferous areas lighter than elsewhere. The three smallest specimens are dull 

 gray rather than yellow and in one specimen a very evident greenish tinge is 

 present actinally. The finest specimens, about 35 mm. in diameter (PI. 121, 

 figs. 1-3 is the type) collected at Westernport, Victoria, March, 1911, have the 

 test very light, almost cream-color; the tube-feet and all the small spines are 

 of about the same shade, but the primaries are deep greenish brown in striking 

 contrast. There are two other specimens with some spines; in one, these are 

 dull purple becoming light at the tip especially around the mouth where the 

 distal half is almost white; in the other, the spines are very pale, almost white, 

 but with a more or less evident purple tinge, especially near base. It is hard to 

 decide whether this diversity in color is characteristic of the species or whether 

 we have several different species included under the name pachistus. 



