[From the American Journal of Science and Arts, Jan., 1863.] 



5. On the classification of the Brachyura, and on the homologies of the 

 . antennary joints in Decapod Crustacea ; by Wm. Stimpson, M.D. — Dr. 

 Strahl has recently been making some carcinolbgical investigations, 

 (see Monatsbericht der Konigl. Akademie der Wissenschajten zu Berlin, 

 1861, and Annals and Magazine of Nat. Hist., London, 1862,) which 

 have led him to propose a new classification of the higher Crustacea. 

 He considers the characters of the external antennae, particularly of their 

 second joint (basicerite), of paramount importance, and would divide 

 the suborder Brachyura, in accordance with these characters, into four 

 groups, namely, 



Orbata, with the first two joints of the antenna only present, the rest 

 wanting, as in Acanthocyclus. 



Liberata, with the basicerite free, as in Oncinopus. 

 Incuneata, with the basicerite wedged in between the pterygostomium 

 and the epistome, as in Cancer. 



Perfusa, with the basicerite completely united with the neighboring 

 parts, as in Stenorhynchus. 



These differences are certainly of great importance, and have not 

 generally received sufficient attention from carcinologists. But they 

 can scarcely be used for the primary subdivisions, as they are not coin- 

 cident with characters of still higher value. By their use we should be 

 required to dismember well-marked groups ; — to separate for instance, 

 Macrocheira from the Maioids and Gecarcinus from the Ocypodoids ; — 

 while strange approximations would occur, as of Oncinopus with Myeli- 

 tis. Experience has long since shown us that it is impossible to group 

 animals upon the variations of a single organ. 



Some of Dr. Strahl's conclusions are so surprising, that they may 

 well require the closest scrutiny before acceptation. For example, he 

 says : "The Leucosice I consider to include only Dana's Leucosidea, with 

 Dorippe and Ethusa. I separate the Calappidce and Matutidw from 

 them, and unite them with the Parthenopinw rejected from the Oxy- 

 rhyncha? This combination is justified " by the agreement in the situ- 

 ation of the afferent canal of the branchial cavity and of the male sexual 

 organs," etc. But the Calappidce are entirely removed from the Par- 

 thenopince in the structure of the mouth-parts ; the buccal cavity is 

 narrowed anteriorly so that the efferent branchial channels terminate 

 at the middle instead of the sides of the endostome, and are covered by 

 the indurated summits of the laciniae of the first pair of maxillipeds 

 (tritocheirognathites). Like the Leucosidea they are oxystomatous, as 

 Milne-Edwards has shown. They indeed differ from these latter in 

 the situation of the efferent canals, and should therefore be sepa- 

 rated as a distinct group ; but they should no more be united to the 

 Parthenopince than should the Dorippidce, which Dr. Strahl would unite 



