's RIJKS MUSEUM VAN NATUURLIJKE HISTORIE — LEIDEN. 223 
front. The outer appearance is much like that of the other species of 
Clistocoeloma; carapace and legs are everywhere covered with a close 
down of short hairs, the postfrontal lobes are little projecting, the front 
is bent obliquely, not perpendicularly, downward, the lateral margins of 
the carapace are toothed anteriorly, and the upper orbital border is very 
oblique. 
Cl. tectum bears a very great resemblance to Cl. balansae A. Milne- 
Edwards, on account of the carapace being quadrate, and the distance 
between the outer orbital angles only slightly or not at all exceeding 
the length of the carapace, and the external postfrontal lobes being sub- 
divided into two small tubercles. It differs by the course of the upper 
orbital border, that is not waved, by the tubercles on the carapace, the 
_ shape of the een of the on probably by some other characters. 
The carapace, as has been said, is quadrate; its surface is somewhat 
curved in a transverse direction, but nearly straight longitudinally, though 
very much uneven. The place of the large tubercles has been indi- - 
cated by Miss Rathbun, and may be seen in my figure: firstly there is 
a tubercle, at the level of the external orbital angle, behind each lateral 
Af lobe, and a much larger one, lying farther backward, behind 
each median be: these tubercles are much better defined anteriorly than 
the postfrontal hes themselves. Secondly there is a somewhat concave 
row of 7 tubercles of difterent size: on the mesogastric region is lying 
the median of these tubercles; at either side of it is found a somewhat 
larger one, and finally there are again two very small ones, laterally 
of the larger one, on the hepatic areas. The cardiae region has three 
rather large tubercles, two anteriorly and one posteriorly, and laterally 
of these there are again two longitudinally-elongated tubercles on the 
inner parts of the branchial regions. These tubercles are not much pro- 
minent, but nevertheless they are very conspicuous in alcohol-specimens, 
on account of their being covered by some longer and thicker hairs, of 
a browny colour, that are at once marked out among the very short, 
greyish or blackish hairs of the general fur. of the carapace, which 
latter hairy covering affords a characteristic general 
dark hue to the animal. When the hairy coating is removed the 
carapace is smooth, shining, minutely punctate. 
The front is bent obliquely-downward, ill-defined towards the post- 
frontal lobes, rather high (3!/, times as long as broad), with concave 
surface, and somewhat projecting anterior margin; the latter bears a 
narrow, distinct emargination in the middle, the lateral parts are sloping 
somewhat obliquely-backward, and each part has two small prominences, 
so that six of them are in all counted; the hairs are somewhat longer 
