CANCROIDEA. 279 



spines, fourteen lines ; length of spine, three lines. The two anterior 

 teeth of the antero-lateral margin point nearly forward, while the four 

 posterior, which are separated from the anterior by considerable space, 

 are directed more outward. The abdomen of the male is somewhat 

 oblong, its length exceeding its basal breadth. 



Genus CilBUPA, Dana. 



Pedes antici sequerdibus vix longiores, 2di 3tii itique longi, gracillimi, 

 tarso valde tenui, bti bene natatorii, tarso elliptico. Articidus antennas 

 externce lmus cylindricus seqiienti similis. Carapax transversus. 



Anterior feet hardly longer than the following pairs, second, third, 

 and fourth pairs long and very slender, tarsus very slender, fifth 

 pair natatory, the tarsus elliptical. First joint of outer antennae 

 cylindrical, and like the following. Carapax transverse. 



The species for which this genus is instituted has the narrow first 

 antennary, joint of Carcinus; yet the posterior legs have an elliptical 

 plate for a tarsus, and the six preceding pairs are very slender, much 

 as in many Amphitrite. It is related to this last-mentioned genus; 

 but in addition to the character of the outer antennas, the male abdo- 

 men in our species has but four segments, the penult articulation 

 common in other genera being here obsolete. Its form is triangular 

 from a broad base. The praelabial plate has the usual dividing ridge. 

 The hand is subtrigonal, but rather short, and the arm projects but 

 little beyond the carapax. The third joint of the outer maxillipeds 

 is about as long as broad, oblique on the outer margin and arcuate 

 within. 



The species is much broader than either those of Carcinus, or Am- 

 phitrite. The name of the genus alludes to the intermediate cha- 

 racter between Carcinus and Lupa. 



Carupa tenuipes. 



Carapax transversus, non areolatus, lasvis, grarmlatus, niidus, fronts 

 integro, medium pauluh emarginato, margine antero-laterali 7-den- 



