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122 Scientific Intelligence, 



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are less numerous, as in the Grapsoidea, The outer antennce are obso- 

 lete, and the inner in Corystoides have no fossettes. They are there- 

 fore genera of low grade, at the foot of the Cancroidea, and approach 

 closely in rank to the Corystoidea. 



Our grand divisions of the Cancroidea are hence, 



1. Cancrinea, or Cancroidea Typica. 



2. Telphusinea or Cancroidea Grapsidica. 



3. Cyclinea, or Cancroidea Corystidica- 



The character of the efferent passage or canal, separating the Leu- 

 cosoid Crustacea or Oxystomata, is the most striking among the 

 Brachyura. While, in all other species, this passage passes over the 

 outer portions of the palate or prjelabia! area, in these, it passes over 

 the medial portions, and terminates at the middle of the front margin of 

 the buccal area which is therefore elongated, giving the area a triangu- 

 late outline : the character of this passage and not the form of the area 

 is the important character of the Leucosoidea, The inner branch of the 

 1st pair of maxillipeds is modified to correspond, as it covers {more 



or less perfectly) in this and all the Brachyura the efferent passage. 



The efferent passage, which affords the striking character alluded to, 

 has its different degrees of perfection among the Cancroidea. In a 

 large number of genera, the waters wash over the palate without any 

 confining ridge: but in others there is a distinct ridge, running longi- 

 tudinally, near the middle of either lateral half of the palate, and 

 terminating at the front margin of the buccal area. This ridge is 

 prominent in Eriphia, RuppeMia, Ozius, Pilumnoides, Melia (as the 

 writer has observed) and some other genera, and is also distinct in 

 Pilumnus. It is wanting in Cancer, Xantho, and the allied, or if a 

 trace is to be observed, (as in Menippe Rumphii and some other spe- 

 cies,) it does not reach to the front margin of the buccal area. We 

 have in this character, therefore, an important distinction separating 

 the non-natatory Cancrinea into two groups, the Cancridae and the 

 Eriphidae, Mere breadth of carapax alone is of very little value as a 

 characteristic: Xantho passes by its allied genera into species but 

 little broader than long, and so with Chlorodlus. 



Among the swimming species, a large part, as detected by De Haan, 

 have a small lobe attached to the inner margin of the inner branch of 

 the 1st maxillipeds: while others, as Plalyonychus and the allied have 

 no such lobe and approximate somewhat to the Corystoidea, although 

 not property, as we tlunk, of that group. 



The species of Lupa and Thalamita have a ridge upon the palate 

 either side bounding the efferent passage; but there is one exception 

 in Lupa cribraria^ which species consequently must pertain to a dis- 

 tinct group from the other Lupas, 



In these brief remarks on the classification of the Cancroidea, we 

 leave much to be gathered from the following synopsis. But a few 

 words should be offered on the genera of De Haan and Edwards; 

 partly because the two are to some extent in conflict, and partly be- 

 cause several of those of De Haan are of unessential importance- 

 The publication of the first fascicle of De Haan's Crustacea of the 

 Fauna Japonica in 1833, preceded Edwards by a year, but the descrip- 

 tions of his genera were so concise and imperfect that it was not possi- 

 ble for any one to have recognized them all. 



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