REPORT ON THE CRUSTACEA MACRURA. 565 



Geographical Distribution. — In the Challenger collection there are species from 

 the Fiji Islands and Cape York. 



Dana records Betseus truncatus from Hermite Island, Tierra del Fuego, where it 

 was dredged in 10 fathoms. Betwus asquimanus from the " shores of Black Eocks, 

 among seaweed, Bay of Islands, New Zealand," and Betseus scabro-digitus from 

 Valparaiso, Chili. 



Stimpson obtained Betseus australis from Port Jackson, among sublittoral seaweed, 

 and Betseus trispinosus at a depth of 6 fathoms in the same locality. 



Betseus malleodigitus, n. sp. (PI. CI. fig. 5). 



Dorsal surface of the carapace (in female) depressed over the cervical fossa. 

 Orbital lobes enlarged, anteriorly produced to an obtuse point. Branchial walls 

 deep, lessening anteriorly and posteriorly from the second pair of pereiopoda. Centre 

 of frontal margin depressed and excavate (fig. 5c), the median line being slightly 

 elevated, the elevation widening posteriorly to the orbital lobes. 



The first pair of antennae is slender and the stylocerite reduced to a minimum. 

 The first joint of the peduncle is as long as the two following joints together. 



The second pair of antennae carries a long and slender scaphocerite, which consists 

 chiefly of a spine that reaches as far as the extremity of the first joint of the peduncle 

 of the first pair of antennas, and scarcely to more than half the length of the terminal 

 joint of the peduncle of the second pair. 



The second pair of gnathopoda has the terminal joint evenly fringed with stiff hairs 

 on each margin. 



The first pair of pereiopoda is unequal in size, that on the right being smaller 

 and more normal ; the propodos is long, ovate, and the dactylos and pollex correspond 

 in length and are about half the length of the palm. The propodos on the left side 

 is large (fig. 5k), thick and rounded towards the carpal extremity, and tapering towards 

 the dactylos, the extremity of which passes the articulation ; the dactylos is short, 

 stunted, and projects in two opposite directions, being shaped like a mallet. 



The second pair of pereiopoda (fig. 5l) is long and slender, the carpos being five- 

 articulate, the three distal articuli being equal, and the two proximal longer and 

 subequal ; the propodos is long and slender and with the dactylos forms a minute chela 

 that is about half the length of the carpos. The posterior three pairs of pereiopoda are 

 wanting, but the joints that remain show the posterior pair to be more slender than 

 the two preceding. 



The lateral walls or coxal plates of the pleopoda are less deep than the 

 carapace. 



