184 ME. B. J. MIERS Olf A ]SEW GENUS 



. tion among the Oxystomata was unsuspected' until my paper on 

 the Oxystomatous Crustacea had been read before the Society. 



AcT^OMORPHA, gen. nov. 



Carapace convex, with the antero -lateral margins arcuate, as in the 

 Caucroidea ; front broad, and slightly concave in front. External 

 antennae with the basal joint apparently fused with the inferior wall 

 of the orbit; the flagellum wanting; the orbital cavity large, and 

 filled with the peduncles of the eyes, the cornea being almost com- 

 pletely concealed by the external wall of the orbit. Buccal cavity 

 broader and less decidedly triangulate than is usual in the Oxystomata. 

 External maxillipeds with the meros-joint triangular, a Httle shorter 

 than the ischiura-joint ; the exognath narrow, and with its outer 

 margin slightly curved. Abdomen of male narrow-ovate, 7-jointed, 

 the two last joints longer than the preceding, the terminal joint 

 triangular, acute. 



ACTiEOMORPHA EROSA, Sp. nOV. 



Carapace everywhere granulated, the granules interspersed with small 

 deep pits. There is a large rounded elevation behind each orbit, one 

 on the cardiac region, and one on each branchial region near the lateral 

 margin. Anterior legs obscurely granulated, robust ; arm very short ; 

 hand -but little longer than the wrist, fingers straight, closely meeting 

 along their inner edges when closed, acute at the tips. Ambulatory 

 legs short, nearly smooth, laterally compressed; tarsi very small, 

 slender, and acute. Length 4 lines ; breadth 4^ lines. 

 Hab. Austraha, Port Curtis (F. M. Rayner, Esq.). 

 This species, of which I have seen but a single example, is dis- 

 tinguished from all the Leucosiidce with which I am acquainted 

 by its form and the structure of the external antennae and of the 

 orbital region. In general appearance A. erosa bears a greater 

 resemblance to such a species as Actcea granulata among the Can- 

 cridoB than to the Oxystomata (hence its name) ; and this resem- 

 blance is borne out by the form of the large orbits, and short 

 robust, anterior legs. That it really belongs to the Oxystomata 

 is evident from the form of the buccal cavity and of the meros- 

 joint of the outer foot-jaws. The eyes, of which the cornea is 

 rudimentary (and nearly concealed, in the specimen I have exa- 

 mined, by the outer wall of the orbit), are perhaps useless as organs 

 of vision. Notwithstanding its small size, this example shows no 

 signs of immaturity. 

 It is perhaps most nearly allied to the genera OreopJiorus* and 



* Oreophorus, Eiippell, Beschreib. 24 Krabben Kothen Meeres, p. 19 (1830) ; 

 Bell, Trans. Linn. Soc, xxi. p. 306 (1856). 



