608 



THE VOYAGE OF H.M.S. CHALLENGER. 



beyond the last joint of the peduncle of the first pair of antennas, six equal teeth on the 

 upper surface, the posterior two being on the carapace ; apex bi-denticulate, inferior 

 margin being armed with two teeth a little behind the apex." 



In the Challenger specimen there are only five teeth on the dorsal crest and rostrum, 

 of which two are posterior to the orbital margin, and three stand on the rostrum, 

 and only one near the apex on the lower margin. The apex is also slightly turned 

 upwards, whereas in Stimpson's description it is said to be straight and bifid, with two 

 teeth on the lower margin. He also describes the frontal margin of the carapace as 

 having no tooth but that which defines the frontal from the lateral margin, whereas 

 in Nauticaris futilirostris the outer canthus of the orbit is defined by a small point or 

 tooth ; another and larger one corresponds with the first antenna, another but rather 

 smaller one with the second antenna, and one still smaller is situated at the fronto- 

 lateral angle. 



The second pair of gnathopoda also appears to be longer in our specimen than in the 

 one described by Stimpson, and the animal is more robust and thick, but this might in 

 part be due to its being a female gravid with ova. 



It may also be compared with Dana's species, Hippolyte brevirostris, 1 which was 

 taken at Dungeness in the Straits of De Fuca, Oregon, but which has only four teeth on 

 the upper margin of the rostrum and none on the lower. 



Nauticaris unirecedens, n. sp. (PI. CX. fig. l). 



Carapace anteriorly crested and produced to a rostrum that is armed on the upper 

 surface with seven equidistant teeth, and one placed further back on the dorsal surface 

 over the gastric region. 



The animal is robust in appearance, the dorso-frontal surface being slightly compressed 

 and elevated to a small carina that is armed on the gastric region with one well-developed 

 tooth, in front of which there is a space without any tooth. On the frontal region, 

 posterior to the orbital margin, a series of seven teeth commences and continues on the 



1 Dana, loc. cit., p. 566, pi. xxxvi. fig. 5. 



