CARCINOLOGICAL STUDIES. 71 



The upper orbital margin presents traces of two fissures, 

 but appears for the rest entire. The outer angles of the 

 orbits are dentiform and acute , and project a little less for- 

 ward than the external frontal teeth. 



The antero-lateral margins (fig. Qb) are shorter thau 

 the postero-lateral ones and measure only two thirds of the 

 latter. They are armed behind the dentiform ^ external 

 orbital angles, with two acute teeth, of which the 

 posterior one is somewhat larger than the other. This third or 

 last tooth is comparatively a little longer and larger in 

 the specimen of Herbst than in our somewhat younger 

 individual. The first antero-lateral , i. e. the extraorbital tooth, 

 is somewhat flattened above , the two posterior ones slightly 

 convex. The distance between the tips of the first and the 

 second antero-lateral teeth is but little smaller than the 

 distance between the second and the third. The lateral 

 margin of the cephalothorax appears very 

 slightly convex between the first and the 

 second as well as between the second and the 

 third antero-lateral teeth. In the original specimen 

 of Herbst the lateral margin is quite straight between 

 the first and the second teeth, slightly convex between 

 the second and third ; in this specimen the anterior margin 

 of the third tooth forms almost a right angle with the 

 lateral margin , in our specimen, however, a concave arcuate 

 line. The postero-lateral margin is obtusely carinate ante- 

 riorly, but this obtuse carina disappears backward and 

 the posterior margin of the cephalothorax is almost as 

 broad as the distance between the second antero-lateral 

 teeth. The lower margin of the orbits (fig. Qa) is concave 

 and entire, and terminates in an acute prominent tooth, which 

 projects about as much forward as the external frontal 

 teeth. The eyes, antennulae, antennae and epistorae are 

 very much like in Geryon tridens. The second joint of the 

 antennal peduncle is a little shorter than the basal joint 

 and reaches alniost to the upper surface of the front; the 

 third joint measures about two thirds of the length of the 



Notes from the Leyden ]Museiim , Vol. X^ll. 



