REPORT ON THE CRUSTACEA MACRURA. 



897 



wanting, being unfortunately broken off on both sides beyond the basisal joint, but the 

 enormous size of the latter indicates that it supported a large appendage, which probably 

 corresponds in form more or less closely with the preceding pair, but is without an 

 eephysis. The internal muscles are very strong and also support this conclusion. 



The first pair of pleopoda is a powerful but single-branched appendage ; the following 

 pairs are all biramose, the terminal pair having the branches subequal and longer than 

 the telson, the outer being armed with a tooth near the distal extremity, which shows no 

 trace of a diaeresis. 



Eretmocans longicaulis, n. sp. (PI. CXLV. fig. 2). 



Carapace less than one-fourth the length of the animal, dorsaDy smooth, except for a 

 small tooth on the frontal crest, and anteriorly produced to a small rostrum. 



Pleon dorsally smooth, having the somites subequal in length. 



Telson as long as the sixth somite. 



Ophthalmopoda projected on a pedicle that is longer than the animal. 



First pair of antennas nearly as long as the animal. 



Second pair of antennas having a scaphocerite equal in length with the first joint of 

 the peduncle of the first pair. 



Length, entire, 



of carapace, 



of pleon, . 



of ophthalmopod, 



of first antenna, 



of scaphocerite, 



of sixth somite of pleon, 



of telson, . 



6 mm. (0 - 2 iu.). 



1-5 



4 5 



C-6 

 5 



2 



0-8 

 1 



Habitat— Station 227, March 27, 1875 ; lat. 17° 29' N., long. 141° 21' E. ; south of 

 Japan. The specimen was taken at the surface. It is labelled " Amphionid, 27 March 

 1875, W. Pacific." 



The carapace, which is one-fourth of the length of the animal, is furnished on the 

 gastric region with a small tooth and anteriorly produced to a small, sharply pointed 

 rostrum. The frontal margin is not furnished with teeth, except the fronto-lateral 

 angle which forms a small one. 



The pleon is smooth and the somites subequal in length ; the telson is rather longer 

 than the sixth somite, and terminates in a sharp point. 



The ophthalmopoda surpass in length that of the entire animal ; the pedicle forms 

 a long, slender, cylindrical stalk, which carries a pear-shaped organ at its extremity, which 

 is furnished with a facetted ophthalmus. 



(ZOOL. CHALL. EXP. FART LII. 1888.) 



Fff 113 



