24 HAWAIIAN AND OTHER PACIFIC ECHINI. 



beyond the general outline of the test. This specimen measures 40 mm. 

 in diameter, the abactinal system 27, showing a proportionally far larger 

 abactinal system than in the smaller specimens measured. 



The median ambulacral zone consists of two outer vertical series of lari^e 

 secondaries with irregularly arranged miliaries, forming two or three indis- 

 tinct vertical rows. In grandis, there is only one irregular median vertical 

 row of miliaries. 



In a specimen measuring 52 mm. in diameter (PI. 32, fig. l) there are 

 six and six interambulacral plates; the abactinal system measures 25 mm.; 

 the genital plates are more rectangular than those of grandis ; the actinal 

 system measures 18 mm. 



In a specimen of 38 mm. there are five and five interambulacral plates ; 

 the abactinal system measures 19 mm. and the actinal system 18 mm. 



In a smaller specimen, 31 mm. in diameter (PI. 32, figs. 5, G) the abacti- 

 nal system measures 15 mm. and the actinal 12 mm. There are five and 

 five interambulacral plates. 



These measurements clearly show that the proportionate increase in 

 height of the test is mainly due to the greater vertical height of the 

 abactinal interambulacral plates in larger specimens than in the smaller 

 ones. 



All of the different kinds of pedicellarine occur in considerable numbers 

 and very closely resemble those o^ grandis. 



The large globiferous pedicellarii\} (PI. 6, figs. 3 and G) are a trifle smaller 

 than in grandis and usually have the stalk shorter, but these differences 

 are not at all constant. These pedicellaria3 occur on the abactinal surface, 

 but usually not within the abactinal system. 



The tridentate pedicellaria) (PI. 6, figs. 7, 2, and o) are smaller than in 

 grandi.H, the valves usually under a millimeter in length, and the stalks still 

 less. They are almost wholly actinal. 



The small globiferous pedicellaria) (PI. G, fig. J,) are usually only about 

 .25 mm. long, tliough the stalk may be three times that. They are abun- 

 dant everywhere. 



This species was collected by the " Albatross " at the following localities. 



Station 3828. Off Lae-o Ka Laau Light, Molokai. Bott. temp. 43.8^ 

 281-310 fathoms. Brk. sh. g. 



Station 3835. Off' Lae-o Ka Laau Light, Molokai. Bott. temp. 55°. 

 160-182 fathoms. Fne. br. s. m. 



