156 DE. J. G. DE MAJSr ON THE PODOPHTHALMOUS 



86. Metaplax ceenulatijs, Gerst. 



Rhaconotus crenulatus^ Gerstaecker, Carcinologische Beitr'dge, ArcMv 

 f. NaturgeschicJite, Jahrg. xxii. 1856, p. 142, Taf. v. fig. 5. 



The collection contains a fine series of eleven specimens 

 (8 c? , 3 2 ) of this rare crustacean*. 



The following may be added to G-erstaecker's description. 



The granulated anterior margin of the buccal cavity is more 

 prominent than the front, as in Selice, so tbat it is distinctly 

 visible when the carapace is viewed from above. This margin 

 presents a small emargination on each side close to tbe external 

 angles, aiid the endostome is longitudinally ridged on each side. 

 The widely-gaping outer foot-jaws are provided with an oblique 

 piliferous ridge, and thus resemble Selice and Paragrapsiis. 

 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 Grerstaecker'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 1883. 



