REPORT ON THE ANOMURA. 215 



Eumunida, are distiuguislied by ii curious modification in the form of the abdomen, 

 which, unlike that of other Gahxtheids, has, become twice folded on itself. Some of the 

 species appear to dwell in the branches of Gorgonise, &c., and the rudimentary nature of 

 the terminal swimming fan points to their leading a sedentary life, which has resulted in 

 the abdomen becoming folded, as there is now no need for keeping it semi-extended. 

 These forms are thus assuming to a slight extent the main feature of the Brachyura. 



Numerous instances occur of abyssal species with a greatly extended range of distri- 

 bution, and of these we may cite what is perhaps the most striking. Munidopsis antonii 

 (A. Milne-Edwards), which was captured by the "Talisman" off the north-west coast of 

 Africa, was taken by the Challenger in the Southern Ocean and off the island of Juan 

 Fernandez, South America. 



An examination of the deep-sea forms in the collection does not afford any insight 

 into the colour which they possessed during life, for long immersion in alcohol has 

 reduced them all to a dull white. It is known, however, that red is the prevailing 

 colour at great depths, and it appears that, in some cases at least, shallow-water species 

 assume this colour when they pass into deeper water. In the summer of 1885, when 

 dredging in Loch Fyne, on the west coast of Scotland, along with Mr. John Murray and 

 other naturalists, we' captured at a depth of 105 fathoms a large number of examples of 

 the shrimp Pandalus annulicornis, Leach, in which the colour was a bright red, whereas 

 specimens from shallow water on the same coast are invariably of the same pale greyish 

 hue as the sandy bottom on which they are usually found. 



In conclusion, it may be stated that the collection of Anomura reported on in the 

 preceding pages is one of the most valuable which has ever been brought together during 

 a single voyage. It has indeed furnished a knowledge of the bathymetrical distribution 

 of the Anomura which previous to the dispatch of the Challenger was almost entirely 

 wanting, and last, though not least, it has very materially added to the number of 

 known species in the group. 



APPENDIX. 



Two species of Anomura, taken in shallow water, off Bahia, were received too late for 

 satisfactory identification and insertion in the Eeport. One is a Hypoconcha, of small 

 size, though an adult female bearing eggs, which is perhaps referable to Hypoconcha 

 panamensis, S. I. Smith, while the other is a species of Petrolisthes. 



