CRUSTACEANS 



broader in proportion to the length, but in having its antero-lateral margins nine-lobed instead 

 of five-toothed. Carcinus m&nas (Linn.), the common shore-crab, though in general shape 

 and appearance very near to the species of Portunus, is readily distinguished by the last pair 

 of legs, in which the terminal joint is narrowly lanceolate, not as in the other genus widened 

 into an oval swimming paddle. Portunus puber, the velvet crab, is well marked by the 

 pubescent or velvety coat to which it owes its specific and vernacular names. Mr. Alexander 

 Meek says, ' The velvet crab is not uncommon near the Longstone, and is sometimes 

 procured also at other of the outlying Fames.' 1 In P. depurator (Linn.) it should be noticed 

 that the part between the orbits, known as the ' front,' has the centre tooth prominent, 

 whereas in P. holsatus this tooth is about on a level with its companions on either side. 

 P. puslllus, Leach, is notably smaller than the other species. 



The Catometopa owe their title to a depression of the ' front,' which is prevalent among 

 them, but which in no way indicates depression of spirits, for this group includes many of the 

 most active, vivacious, and enterprising crabs that anywhere exist. In this county it is 

 represented only by one of its hundred members, the little pea-crab, Pinnotheres pisum (Linn.), 

 of which Mr. Meek reports that ' A male was got four miles off Seaham, 291)1 September, 

 1897.'* Small as the female is, the male is much smaller. Also his coat is much more 

 firmly calcified than hers. In Bell's opinion the remarkable softness of the female is ' doubt- 

 less the cause of its requiring the efficient protection of the shells of Mollusca.' * The 

 speculative philosopher in these days would rather argue that it is the consequence, not the 

 cause ; just as one may feel certain that hermit crabs have acquired soft twisted tails through 

 residing in firm spiral shells, not that they took to those shells because their tails were soft 

 and twisted. 



The Oxyrrhyncha, or 'sharp beaks,' commonly have the front produced to form a 

 rostrum. Of these Hyas araneus (Linn.) is recorded by Mr. George Tate from the Fame 

 Islands, and by Dr. Johnston in the Lindisfarne Catalogue along with Stenoryncbus phalangium ; 

 Bell quotes Stenoryncbus tenuirostris and Inachus dorsettensis from Embleton's list of the Crustacea 

 of Berwickshire and North Durham; Dr. Norman in the dredging list for 1864 adds 

 Inacbus dorsettensis and Hyas coarctatus as found on the Durham coast.* All these spider crabs, 

 as they are called from the spindly legs of many among them, have the custom of costuming. 

 They do not for this purpose use the spoils of vegetables or of other animals as we do, but 

 the living organisms themselves, which they either allow to settle on their backs or forcibly 

 instal, many parts of the carapace and limbs being provided with hairs and spines of various 

 forms to secure the adhesion of their selected garments. Of the three genera above mentioned 

 Stenoryncbus or ' narrow beak ' is more properly called Macropodia or ' long foot,' name and 

 synonym together intimating two of the characters. The two species should be named 

 respectively M, rostrata (Linn.), with the longirostris of Fabricius for a synonym, 6 in which 

 the rostrum is shorter, and M. tenuirostris, Leach, in which it is longer, than the peduncle 

 of the second antennae. Here the eyes are not retractile as they are in the other two genera. 

 In Hyas the pleon or tail has all its seven segments distinct in both sexes, whereas in the 

 other two genera this part has the last two segments coalesced. Between H. araneus (Linn.) 

 and H. coarctatus, Leach, the most obvious difference consists in the circumstance that the 

 carapace of the latter behind the post-orbital process has a strong constriction, to which the 

 specific name coarctatus alludes. The French authors MM. Alphonse Milne-Edwards and 

 E. L. Bouvier further observe that the first free joint of the second antennae is broader in 

 front in this species than in the other, and that the hairy crest on the sternum or ventral 

 surface, which is continuous in H. araneus, is here interrupted at the centre. That H. coarctatus 

 is the smaller of the two, or that its ambulatory legs are relatively shorter, can scarcely be 

 maintained in face of the measurements which they give. 6 For distinguishing Inachus 

 dorsettensis (Pennant) from /. dorynchus, Leach, the same authors have drawn attention to 

 differences in the third maxillipeds, the fourth joint of these organs in the former species 



1 Northumb. Sea Fisheries Committee Rep. for the year 1902, p. 65. 



8 Op. cit., p. 66. 



8 Brit. Stalk-eyed Crustacea, p. 1 20 (1853). 



* To save repetition it may suffice to say that Mr. George Tate's records are all quoted from the 

 Hut. of the Berwickshire Naturallitf Club, iii. 328 ; those of the Lindisfarne Catalogue from pp. 48, 

 49, in the volume of the same history published in 1876 ; and Norman's dredging lists for 1863, 1864, 

 from the Nat. Hut. Trans. Northumb. and Dur.,\. 23-26 (1867). 



6 M. J. Rathbun, in Proc. Bio/. Soc. Washington, xi. 155 (1897). 



6 Resultats des campagnes de FHirondelle, vii. 19 (Monaco, 1896). 



152 



