TEMNOTREMA HAWAIIENSIS. 319 



Genital plates not marked by a transverse line; tubercles on coronal 

 plates not in horizontal rows; more or less green on test, or if 



green is lacking, test is bright red hawaiiensis. 



Pits small, the distance between the two of same horizontal interambulacral suture 



greater (often much greater) than the length of one. 



Ambulacral plates equal interainbulacral in height and number; test variegated 

 gray and whitish; spines reddish at base, often with a small dark band 



distally; genital plates marked with a transverse line sculpla. 



Ambulacral plates lower and somewhat more numerous than interambulacral; 



test red; spines red with white bands; no transverse line on genital plates . . ruber. 

 Buccal plates only 5; anal plates very numerous, subequal, with no distinct suranal . . Doderleini. 



Temnotrema hawaiiensis, comb. nov. 



Pleurechinus hawaiiensis A. Agassiz and Clark, 1907. Bull M. C. Z., L, p. 244. 



Plate 99, figs. 1-3. 



The specimens at hand of this pretty species range in horizontal diameter 

 from 5 to 9 mm. The vertical diameter ranges from about two thirds to three 

 fourths of the horizontal. The test is therefore quite high and it is well arched. 

 The actinostome of the largest specimen is 4 mm. across, while the abactinal 

 system is only 3 mm. The longest primary spines are only a little over 3 mm. 

 long. There are 12 interambulacral plates in each column and the number of 

 ambulacrals appears to be the same. In the mid-zone, the interambulacral 

 plates carry at the centre a small primary tubercle, on each side of which is a 

 distinct secondary, and on the upper half of the plate, in an irregular, curved 

 series are 4-6 smaller secondaries. The pits are very large and occupy most of 

 the lower half of each plate. Of course, the tubercles are fewer and the pits 

 smaller as the ocular plate or the peristome is approached. In the ambulacra 

 the number of tubercles on each plate is less and the pits are smaller. The pit 

 at the outer corner of each plate is insignificant or wanting. The genital plates 

 (PI. 99, fig. 3) are of moderate size, pentagonal, and a little elevated; there is a 

 tubercle (rarely two) on the proximal margin, and the rather large genital pore 

 is just distal to the centre of the plate. The madreporite is very inconspicuous 

 as the pores are comparatively few. The oculars are small and completely 

 exsert ; each one carries a couple of very small tubercles. At the proximal end 

 of each ocular is a more or less conspicuous pit. The periproct is covered by a 

 small number of plates (4-10) among which the suranal is usually easily dis- 

 tinguishable. The anus is approximately central. The actinostomal membrane 

 (PI. 99, fig. 2} is very thin and bare. The buccal plates are very small, and 



