REPORT ON THE CRUSTACEA MACRURA. 291 



The second guathopod is broken in all the specimens, so that I cannot compare its 

 length with other parts, except so far as to show that the basecphysis is relatively the 

 same as in Haliporus curvirostris. 



The pereiopoda are long and slender, especially the posterior two pairs. 



Only one specimen of the male, and that considerably damaged, was taken off the 

 Philippines. Neither the ventral surface of the male, nor the petasma attached to the 

 first pair of pleopoda, is perfect enough for description. The female has the sexual 

 tubercular process on the third pair of pereiopoda very large, and covered with stiff, short 

 hairs ; posterior to which, arising from the ventral surface on each side, is a stout process 

 directed backwards and inwards and sparsely covered with short hairs. In the median 

 line between these processes is a narrow, straight-sided vertical projection, broken at the 

 apex, and posteriorly is the lateral bar, marking the posterior limits of the pereion, and 

 on the first somite of the pleon, between the pleopoda, is a pointed process beneath 

 which a nervous ganglion lies. 



The specimens are all of a semitransparent and submembranous structure, and live at a 

 depth of about three miles, where the temperature is only 4° - 6 F. above the freezing 

 point. 



The solitary female specimen, taken near the Philippine Archipelago, does not on the 

 closest comparison exhibit any difference from the Atlantic specimens ; it was captured at a 

 depth of one mile and a quarter, and where the temperature was 5° F. above freezing point. 



Haliporus neptunus, Spence Bate (PI. XLII. fig. 3). 

 Haliporus neptunus, Sp. B., Joe. cit. 



This species closely resembles Haliporus equalis, and a very close comparison of the 

 two species externally has failed to show that there is any differentiating feature to 

 distinguish them, except that in Haliporus neptunus the flagella of the superior antennas 

 are shorter, and the form of the parts on the ventral surface of the pereion differs. 



The coxal process of the third pair of pereiopoda in the female is large and Like the 

 same part in Haliporus equalis ; there is a transverse lunate process behind them, but 

 the coxal process of the fourth pair of pereiopoda is rounded instead of being sharp ; and 

 posteriorly in the median line is a narrow longitudinal prominence, instead of the broad 

 shield-like plate as in Haliporus equalis. In the male the petasma between the first 

 pair of pleopoda terminates in three prominent processes like a trident, hence the specific 

 name. 



Length (male and female), 63 mm. (2"5 in.). 



Habitat.— Station 191, September 23, 1874 ; lat. 5° 41' S., long. 134° 4' 30" E. ; off 

 the Arrou Islands ; depth, 800 fathoms ; bottom, green mud ; bottom temperature, 39°"5. 

 Trawled. Two specimens. 



