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MAIOPSIS. 



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The orbital region of A, hi/slrix does not differ from that of A. rissoana 

 but for the presence of a pro3ocular spme, a cliaracter which by itself cannot 

 bo considered of generic importance, as Mr. Miers admits * Through hystrix 

 we pass by a gentle transition to such species as ttmhonata^ carpenteri^ and 

 cra8sa (species placed in the genus Scyramatliia)^ in which the orbit is better 

 defined through the projection of the brow. 



Thus the passage from the Inachine to the Maiine type is so gradual as 

 hardly to justify a flxmily division such as is proposed by Mr. Miers.f In 



the series of species, all of which are assigned to the genus AncmiatJda, family 

 Imcldd(£, by Mr. Miers % {rissoana, hystrix, pulchra, crassa), we pass from the 

 strictly Inachine orbit of rissoana to an orbit like that of crassa, which is 

 practically the same as that of Choriiia longipes, a species assigned by Miers 

 to the genus ILjaslcnus in the family Maiidce, 



The orbital region is subject to a great amount of variation even in a 

 single species {A. iimhonata), so that within the bounds of mere individual 

 variation the passage is made from the Inachine to the Maiine type of orbit 

 as exhibited in Choriiia. 



'^ 



MAIOPSIS Fax. 



Bull. Mus. Comp. Zool., XXIV. 150, 1893. 



Carapace sub triangular, as broad as long, spinose ; rostrum produced 

 anteriorly into two divergent horns with an accessory spine upon their 

 outer margins ^ interorbital space broad. Eyes small, eycstalks slender, 

 retractile within the orbits. Orbits large, with a forward aspect, incomplete 

 below, the upper margin prominent, with two deep fissures, and supraocular 



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spines. Epistome short. Basal segment of antenna} very broad, with three 

 prominent spines upon its anterior margin ; flagellum of the antenna) widely 

 separated from the cavity of the orbit by a broad process of the basal seg- 

 ment. Merus of outer maxilHpeds notched at the antero^nternal angle. 

 Leo's of moderate length ; carpus of chelipeds elongated, not carinated; chela 

 elongated and slender, fingers canaliculate within, but not spoon-shaped at 

 their tips, their prehensile edges meeting throughout most of their length, 



* Journ. Linn. Soc. London, Zool, XIV. 658, 1879. 



f Op. clt., p. G40. 



X Challenger Erachyura, p. 26, 1886. 



§ See M. J. Uailibun, Proc. U. S. Nat. Mus., XVIL 61, 69, Plate I., 1S91 Cf. Pig. 3 (orbit of 

 A. umbonata) with Pig. 1 (also A. umhonata), and then cf. Pig. 1 with Pig. 5 {Choriiia longipes). 



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