76 DR. J. G. DE MAN ON THE PODOPHTHALMOUS 
dividuals. In most examples the ridge on the basal joint of the 
outer antenne is provided with a row of very short, small spines ; 
in some specimens, however, as in the largest male from Elphin- 
stone Island, these spines coalesce into a denticulated laminiform 
crest, such as that described by Stimpson in the Japanese Thala- 
mita picta; but in other individuals again this ridge is only 
armed with some acute granules of unequal size. 
As the internal lobes of the upper orbital margin (outer frontal 
lobes) have probably a constant form in each species, it may be 
possible by them to distinguish the different species of this 
difficult genus. Thus these lobes are nearly straight in Thalamita 
Dane, Stimps., but somewhat arcuate in 7. prymna. 
In all these specimens, even in the small individuals from King 
Island and in the very young male from Elphinstone Island, the 
outer surface of the hand is armed with a granulated crest between 
the elevated ridge, near the inferior margin, which runs on to the 
immobile finger and the spines of the upper surface. They thus 
differ in this character from the Red-Sea individuals described 
by me some time ago under the name of Thalamita prymna (Notes 
from the Leyden Museum, vol. 1i. 1880, p. 180); for in the latter 
the crest does not occur, when they are less than 45 millim. broad, 
but only gradually begins to appear when they have attained 
that size. The Mergui specimens and those from the Red Sea, 
therefore, are either varieties of one species, or they belong to 
different forms. In the latter case, I propose to distinguish the 
Red-Sea specimens as Thalamita picta, a species still very im- 
perfectly known and insufficiently characterized. One character 
mentioned as distinctive between these two forms, viz. the occur- 
rence of an acute prominent crest on the basal joint of the 
external antenne, occurs sometimes in specimens of Thal. prymna, 
as I have described above. | 
Thalamita prymna is found in the Indian Ocean and the 
Malayan Archipelago (Padang, Timor, Halmahera). It has also 
been recorded from the coast of New Caledonia, the Loo-Choo 
Islands, and Japan. 
The occurrence in the Red Sea of the typical Z. prymna, 
as now characterized, is a little doubtful. 
58. THALAMITA SPINIMANA, Dana. (PI. LV. fig. 7.) 
Thalamita spinimana, Dana, United States Expl. Exp., Crust. part i. 
