16 DR. J. G. DE MAN ON THE PODOPHTHALMOUS 
each pair, meet one another posteriorly at the tubercle of 
the posterior cardiac region. The anterior one of these two 
tubercles, that lies on the mesobranchial region, is rather acute 
in H. Pleione, and the posterior, though also blunt and obtuse, 
is nevertheless more prominent in Herbst’s species. The 
epibranchial lobes, which are situated on each side of the 
cervical suture, are provided in H. Hilgendorfi each with two 
small, little prominent, obtuse tubercles, lying behind one 
another; in H. Pletone these two tubercles are conical and acute. 
Immediately behind the external angles of the orbits a small denti- 
form, rather obtuse tubercle is found on the hepatic region of the 
cephalothorax, which also occurs in H. Pleione. The lateral 
sides of the upper surface of the cephalothorax are moreover 
armed in our species, as in Plezone, with some small dentiform 
tubercles, which are situated behind the tubercles of the epi- 
branchial and hepatic regions and the bases of the legs, close to 
the latter. One of these dentiform tubercles is found, in both 
species, quite above the base of the chelipedes; behind this 
tubercle in H. Hilgendorfi four small dentiform tubercles occur, 
whereas in H. Pleione there are only two. I may add that these 
four tubercles are arranged rather irregularly and that they 
are often of a somewhat different size. Between the external 
angle of the anterior margin of the buccal cavity and the denti- 
form tubercle, which is found above the base of the anterior 
legs, in both species, two other dentiform tubercles occur, the 
anterior of which is twice as broad as the posterior. 
The spines of the rostrum are comparatively a little longer than 
those of H. Pleione (Dr. Hilgendorf informs me that the rostral 
spines have been drawn too long in Herbst’s figure of H. Pleione 
(pl. lvii. fig. 5). In the male of our species the proportion of 
the length of the cephalothorax to the distance of the two 
parallel imaginary lines, which unite respectively the tips of the 
rostral spines and the anterior angles of the supraorbital margins, 
is as 15to11j; in the female individuals this proportion is as 15 
to 74. The rostral spines are thus comparatively shorter in the 
female ; but I may observe that this condition may perhaps be 
ascribed to the younger age of the female specimens, which are 
much smaller than the male. The rostral spines are quite as 
divergent as those of H. oryx (Nouv. Arch.du Muséum Hist. Nat. 
t. vili pl. 14. fig. 1). In H. Hilgendorfi the rostral spines are 
directed nearly horizontally forward, so that they make a very 
