DECAPOD CRUSTACEANS OF THE BEAUFORT, N. C, REGION. 433 



The time required by the young crab to pass through the zoea and megalops stages to the first 

 crab stage is not known, but it is probable that young hatched during the summer complete their trans- 

 formation before winter. By this time they are about 3 millimeters wide. They probably grow little 

 if at all during the colder months, but early the next spring are ready to begin their active predatory 

 life. If an adequate supply of food is obtained they grow quite rapidly, molting at first at intervals of 

 about a week and later at intervals of about a month, increasing about one -third in width at each molt. 

 By the end of the second summer they have reached a width of from 75 to 100 millimeters. 



In both sexes mattirity is probably reached in the third or fourth summer after hatching. The full- 

 grown male measures over 160 millimeters from tip to tip of his lateral spines and is about as active and 

 pugnacious an animal as is to be found in the water. The females are somewhat smaller and have 

 weaker chelipeds, but they can inflict a very painful bite and will fight savagely if surprised and retreat 

 is impossible. Diuing the molt at which the female reaches matiuity her abdomen loses the triangular 

 shape which it has had through the earlier molts; it becomes broad and roimded and lies loosely on the 

 ventral side of the thoracic sterna. A day or two previous to this molt, imder normal conditions, she 

 has been taken up by some male who carries her about imtil her shell is ready to be cast, guards her dur- 

 ing the process, and immediately afterwards mates with her. It is believed that she never mates again, 

 although she may produce more than one lot of eggs, and it is probable that she never molts again. The 

 male also probably does not molt after reaching matiurity, but he will mate repeatedly with different 

 females if he has an opportunity to do so. 



The courting habit of the male, referred to by Prof. Verrill a and others, is very interesting. The 

 " dancing and strutting" is done immediately before the female is taken up to be carried about and does 

 not appear ever to be enacted except before a female that is about to cast her shell . The attitude of 

 the female at such times appears to be one of interest and submission. How soon eggs are produced after 

 mating is not known, but there are reasons for believing that it is not for several weeks and possibly not 

 until the next season. It is not at all likely that two lots of eggs are produced in one summer, although 

 well-developed eggs may be found in the ovary of a female that has just hatched one lot. 



Having reached matiuity the crab probably lives three or four years. Its enemies, aside from man, 

 do not appear to be numerous and against them it is ordinarily able to defend itself if escape is not prac- 

 ticable. Its shell, however, affords a convenient lodging place for barnacles and bryozoans and its 

 gills and gill chambers become clogged with clusters of a little stalked barnacle (Octolasnia darwini) all 

 of which doubtless help to weaken it and to make it an easy victim of some hungry fish or a summer 

 storm. Observations made during the summer indicate that the mortality is greatest among the old 

 females at that season of the year, but it may be that the males die and are destroyed in deeper water so 

 that their shells are not cast on the shore. When laden with eggs the females seek comparatively shal- 

 low water and at times have been observed in numbers close to the edge of the deep channels which run 

 along the inside of Bogue and Shackleford Banks. 



Two specimens of dwarf females, both mature, have been collected at Beaufort. The smaller of 

 these measiues only 35 mm. long and 80 mm. wide. 



Callinectes omatus Ordway. PI. xxxiv, fig. 2. 



Callinedes omatus Ordway, 1863, p. 571; Rathbun, 1895, p. 356; ibid, 1901, p. 48: Verrill, 1908, p. 366. 



Carapace of approximately the same proportions as in C. sapidus; somewhat tumid and finely granu- 

 late throughout, transverse lines distinct; frontal teeth, including the inner orbitals, 6; anterolateral 

 spines shallow and broad, the tips of the first five or six acute, the others acuminate; lateral spines 

 curved forward and hardly as long as the space occupied by the three preceding teeth ; inner suborbital 

 angle prominent but hardly acute. First segment of abdomen of male produced laterally into an acute, 

 upturned spine. Chelipeds formed as in C. sapidus but with the spines probably more acute, the 

 ridges of the manus more developed and the teeth on the fingers larger and sharper. 



Length of a male, 33 mm. ; width, 74 mm. 



Color, clear grayish or bluish green with red on the fingers and more or less brilliant blue on the 

 front of the chelipeds and terminal joints of the legs, merging into dark blue or purple at the articula- 

 tions; lateral spines and lower surface of chelipeds and teeth of chelae ivory white. 



o 1,0c. dt., p. 371, 372. 



