REPORT ON THE CRUSTACEA MACRURA. 887 



Posterior pair of pleopoda shorter than the telson. 



Length, entire, . .... 



,, of carapace, .... 



„ of rostrum, .... 



„ of pleon, .... 



„ of sixth somite of pleon, 



Habitat. — April 3, 1874; off Cape Howe, Australia. Two specimens were taken at 

 the surface at night. 



The carapace is dorsally smooth, but slightly depressed over the gastric region, 

 anterior to which, on the frontal region, the crest is elevated and anteriorly produced to a 

 rostrum that is a little longer than the carapace ; it is serrate on the upper margin with 

 thirteen teeth, of which the posterior two are postorbital and supported by a small tubercle, 

 and the anterior is distant from the apex of the rostrum ; the under margin is smooth 

 and arcuate towards the base for one-half the length of the rostrum, beyond which it is 

 armed with six teeth, the most distal of which is distant from the apex, but beyond the 

 distal tooth on the upper margin. The frontal margin is armed witb a long and slender 

 supraorbital tooth (fig. lc), which stands at the upper margin of the orbit, and is continu- 

 ous with a ridge that strikes the dorsal median line near the pyloric region ; the outer 

 canthus of the orbit is rounded, and beyond it there stands a small first antenna! tooth, 

 whence the marginal fine descends slightly posteriorly to the fronto-lateral angle, which 

 is produced to a long and slender tooth, posterior to which on the lateral margin are four 

 strong teeth that gradually decrease in size, and behind them the lateral margin is smooth 

 to the posterior margin of the carapace. 



The pleon is dorsally smooth and all the somites are subequal in length until the sixth, 

 which is a little longer than the preceding, and is also narrower and less deep. 



The telson is longer than the sixth somite. 



The ophthalmopoda are long in the stalk and pyriform, and reach to half the length 

 of the rostrum. 



The first pair of antennae is excavate on the upper surface of the first joint, which is 

 subequal in length with the ophthalmopoda, and is armed on the outer margin with a 

 short stylocerite. The second and third joints are short, cylindrical, and continuous with 

 the first ; there are scarcely definite articulations separating the joints which support the 

 flagella, the outer of which is the more robust and strongly multiarticulate, the inner 

 being more slender and obscurely multiarticulate. 



The second pair of antennas is broken off in the typical specimen at a point about 

 equal to half the length of the animal, but from its diameter I should judge that when 

 perfect it is at least twice as long. The peduncle is short and supports a scapho- 

 cerite that is longer than the ophthalmopod, subfoliaceous, having the margins parallel 



