REPORT ON THE ANOMURA, 41 



Lithodes is merely a liiglily specialised Pagurid (he considers it to be derived from 

 Eupagurus), which has assumed certain Brachyuran characteristics. A somewhat 

 similar parallel is seen in the case of Blrgus and Ccenobita, though the distinction 

 between the two latter is less strongly marked. In the Lithodids the abdomen has 

 become bent under the cephalothorax, though its primitive asymmetry is still retained 

 and the appendages of the penultimate segment have entirely disappeared. 



The term Paguridea has been retained in order to ensure uniformity of nomenclature 

 among the subtribes of Anomura, though it is of course now used in a much wider 

 sense than that proposed by Dana. 



Section A. LITHODEA, 



Homolicns, Milne-Edwards, Hist. Nat. des Crust., t. ii. p. 180, 1837, in part. 

 Lithodeacea, De Haan, Crust. Japon., p, 213, 1850. 



Lithodea, Dana, U.S. Explor. Exped., vol. xiii.. Crust., part i. p. 401, 1852. 

 Litlwdidca, Stimpson, Proc. Acad. Nat. Sci. Philad., p. 68, 1858. 



Carapace broadly ovate, uneven, with a prominent median rostrum in front, the 

 regions well defined. Chelipedes and the three anterior pairs of legs well developed, 

 cylindrical or subcylindrical, the posterior pair slender, chelate, folded in either branchial 

 chamber. Abdomen bent under the thorax, composed of seven segments, the first of 

 which is of small size and fused dorsally with the second ; abdominal appendages only 

 present in the female, consisting of a rudimentary pair on the first segment, and a single 

 uniramous appendage on each of the four following segments (in Hapalogaster , Stimpson, 

 the first of these is biramous). These last appendages are situated on the left side of 

 the abdomen, which is more or less enlarged at the expense of the other side. Legs 

 widely separated by broad thoracic sterna. Antennular peduncles cylindrical and of 

 moderate size, with short flagella. 



The members of this group (which form but a single family) inhabit the temperate 

 and colder regions of both northern and southern hemispheres, where they live for the 

 most part in shallow water ; certain species have, however, been recently taken at great 

 depths. 



(ZOOL. CHALL. KSP. — PART LXIX. 1887.) ^ZZ 6 



