156 DR. J. GQ. DE MAN ON THE PODOPHTHALMOUS 
86. MErAPLAX CRENULATUS, Grst. 
Rhaconotus crenulatus, Gerstaecker, Carcinologische Beitrage, Archiv 
f. Naturgeschichte, Jahrg. xxii. 1856, p. 142, Taf. v. fig. 5. 
The collection contains a fine series of eleven specimens 
(83,389) of this rare crustacean”, 
The following may be added to Gerstaecker’s description. 
The granulated anterior margin of the buccal cavity is more 
prominent than the front, as in Helice, so that it is distinctly 
visible when the carapace is viewed from above. This margin 
presents a small emargination on each side close to the external 
angles, and the endostome is longitudinally ridged on each side. 
The widely-gaping outer foot-jaws are provided with an oblique 
piliferous ridge, and thus resemble Helice and Paragrapsus. 
The infraorbital ridge is continued backwards in the male nearly 
to the level of the middle of the second antero-lateral tooth ; it 
is entire for a short distance, namely, from the inner angle 
to a little beyond the middle of the eye-peduncles, but thence 
appears finely crenulated to the posterior end; these granules, 
which gradually decrease in size backwards, are about 25 in 
number. In the female the ridge is not continued behind the 
orbits, and presents a row of about 25 minute, more or less 
truncated teeth along its whole length. 
The male abdomen measures nearly a third of the breadth of 
the sternum; the first or terminal joint is triangular, nearly as 
long as broad at the base, and rounded; the second is much broader 
and longer, and almost quadrate, being scarcely broader than 
long; the three following joints gradually increase a little in 
breadth, decreasing in length; the sixth is extremely short and 
a little narrower than the fifth, and the seventh, or basal seg- 
ment, is cristate, and occupies nearly the whole breadth of 
the sternum between the bases of the last pair of legs. The 
lateral margins of the abdomen are fringed with short hairs. 
The first or terminal segment of the female abdomen is partially 
pushed into the penultimate. 
The chelipedes of both males and females are equal to one 
another; it is probable therefore that Gerstaecker’s specimen, 
the right leg of which was much larger than the left, was an 
* M. crenulatus was not represented in the extensive collection of the Leyden 
Museum until 1888. 
