46 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 
Remarks.—As will be explained in my Monograph of the Echinoi- 
dea, vol. 3, pt. 2, this form is not related to 7. siamense, but to 7. macu- 
latum, of which it may perhaps be only a color variety, like 7’. pai- 
lescens H. L. Clark. But in any case it is so characteristic in its uniform 
red or purplish color that it must be kept separate, be it as a distinct 
species, as I think preferable, or only as a variety of 7’. maculatum. 
TEMNOTREMA RETICULATUM (Mortensen) 
Pieurechinus reticulatus MorTENSEN, in de Meijere, Siboga Echinoidea, p. 202, 
1904. 
Locality.—Station 5400; north of Cebu; Tanguingui Island Light 
bearing N. 77° W., 22.5 miles distant (lat. 11°24’24’”” N., long. 
124°05’30’"" E.) ; 46 meters; sand and shells; March 18, 1909. One 
specimen. 
Remarks.—The specimen taken by the Albatross off Cebu is a well- 
preserved and perfectly typical specimen. In spite of its small size, 
4.5 mm. in diameter, it is adult. The species apparently does not 
reach a larger size than about 5 mm. in diameter. 
This species has never been properly described. In his Stboga 
Echinoidea de Meijere mentioned the species Plewrechinus reticulatus, 
characterized by its thorny spines and its large suranal plate, dis- 
tinguished by me among the specimens he had identified as Plewre- 
chinus bothryoides. He refers to the description that was to be given 
in my work on the Siam Echinoidea. In the meantime, however, I 
had come to the conclusion that the form I had distinguished as 
Pleurechinus reticulatus should rather be united with P. scillae 
(Mazzetti), and so I withdrew reticulatus as a synonym only of P. 
scillae. Thestudy of the rich material of these forms that I collected 
in the Malay Archipelago in 1922 and 1929, and in the Gulf of Suez 
in 1936, has, however, convinced me that the form originally dis- 
tinguished as P. reticulatus is so characteristic and constant that it 
must be regarded as a distinct species, the name of which is thus 
to be Temnotrema reticulatum (Mortensen). <A full description of 
this species will be given in vol. 3, pt. 2, of my Monograph of the 
Kehinoidea. 
Genus MICROCYPHUS L. Agassiz and Desor 
MICROCYPHUS EXCENTRICUS, new species 
Characters.—The single specimen is a small one, 17 mm. in hori- 
zontal diameter and 11 mm. high. It is distinctly pentagonal, 
shghtly sunken in the interambulacra. The naked areas in the 
ambulacra as well as in the interambulacra are broad and sharply 
delimited against the tuberculated part of the plates. The primary 
