DECAPOD CRUSTACEANS OK THE BEAUFORT, N. C, REGION. 457 



Macrocoeloma trispinosum (Latreille). PI. xxxvm, fig. 11. 



Pisa Irispitwsa Latreille, 1825, p. 142. 



Pericera trispino^a H. Milne- Edwards. 1834-1840. 1. 1, p. 336; A. Milne-Edwards, 1880, p. 52. 



MacTocwloma trispinosum "Miers, 1879b, p. 665; Rathbun, 1901, p. 74: Verrill, 190S, p. 414. 



Carapace irregularly triangular, with a velvety covering of short brown hairs; the mid-dorsal region 

 much elevated and bearing four low rounded tubercles, one on the gastric, one on the cardiac, and one 

 on each epibranchial region; posterolateral angle prolonged into a strong flattened spine which is 

 directed outward and somewhat backward; posterior margin with a broad, triangular projection the 

 tip of which may be slightly recurved; front formed of two somewhat flattened horns which are nearly 

 parallel at the base but gradually curve away from each other at the tip. 



Basal article of antenna with its inner angle produced, greatly exceeding the frontal margin and 

 forming on each side of the bifurcate rostrum a broad spine directed obliquely outward. 



Chelipeds weak; the meros nodose; the hand small with short fingers, the movable one of which 

 is lightly furrowed above. 



Length of a male, 27 mm.; width, 25 mm. 



One young individual of this species has been found among seaweeds in the harbor. Others have 

 been found outside the harbor in floating masses of Sargassum and it has been brought up in the dredge 

 at the Blackfish Banks. 



Macrocceloma camptpcenun (Stimpson). PI. xxxvm, fig. 12. 



Pericera camptocera Stimpson, 1870, p. 113; A. Milne-Edwards, 1873, p. 57. 

 Macrocceloma camptocera Miers, 1886, p. 79, 80; Rathbun, 1892, p. 249; ibid, 189S, p. 257. 



Carapace irregularly triangular, sparsely covered with light -colored, stiff, curled hairs and with 

 four strong spines on the dorsal region — one on the gastric, one on the cardiac, and one on each epi- 

 branchial lobe; posterolateral angle prolonged into a strong, acute, conical spine directed obliquely 

 outward and backward; posterior margin with a conical, acute, somewhat recurved spine; front com- 

 posed of two rather strongly divergent horns. 



Basal article of antenna with its inner angle produced into a rather slender, curved spine which 

 is directed obliquely outward and forward about midway between the orbit and the rostral horn. 

 Chelipeds weak, smooth throughout; hand small, fingers short and not grooved above. 



Length of a female, 24 mm.; width, 20 mm. 



Color, a dirty brown. 



Two specimens were obtained by the Fisk Hawk on the fishing banks in water 14 fathoms deep. 



Genus MITHRAX Latreille. 



Mithrax Latreille, 1817, p. 23. 



Trachoniles Latreille in Desmarest, 1S33, p. 263. 



Miihraculus White, 1847, p. 7. 



KEY TO THE SPECIES OF THE BEAUFORT REGION. 



a. Carapace with oblique, parallel branchial grooves .forceps. 



aa. Carapace without oblique, parallel branchial grooves. 



6. Rostral horns about as long as broad depressus. 



bb. Rostral horns shorter, broader than long pkuracanthiis. 



Mithrax forceps (A. Milne-Edwards). ,P1. xxxvni, fig. i. 



Mithraculus forceps A.Milne-Edwards, 1873-1880 [1875], p. 109. 



Mithraculus hirsutipes Kingsley, 1880, p. 389. 



Mithrax forceps Miers, 1886, p. 88; Rathbun, 1901, p. 70. 



Carapace about one-fifth wider than long, deeply sculptiured in the young but becoming smoother 

 with age; anterolateral border with four tubercles (apart from the outer orbital spine) the last two or 

 three of which are usually acute and turned forward at the tip; from near the bases of the first, second, 

 and third teeth three broad grooves run diagonally backward over the branchial area thus leaving two 

 well-defined imbroken ridges on this part of the carapace; the cardiac and gastric regions are crossed 

 by less sharply defined ridges which are more or less broken up into low, roimded tubercles; front 

 with a broadly V-shaped, median notch on each side of which is a rounded lobe; superior and inferior 

 anteorbital teeth of about equal size and not greatly exceeding the postorbital teeth. 



