REPORT ON THE CRUSTACEA MACRURA. 865 



resemblance, particularly in the feeble condition of the posterior pair of leo\s, but it 

 differs in the character of the branchiae, the form of the third pair of pereiopoda, and in 

 the manner of carrying the ova. 



I have not examined the plan of the nervous system nor the development of the 

 embryo, but anticipate that they will be found to be more in accordance with those of 

 the Pbyllobranchiata than with those of the Dendrobranchiata. 



Geographical Distribution. — The species of this genus at present known are not 

 numerous, and the specimens scarcely more so. Pasiphsea sivado, Itisso, is found in the 

 Mediterranean and in the Scandinavian seas, where it was taken at the depth of 100 

 fathoms. 1 Pasiph&a tarda, Kroyer, has also been found in the Norwegian waters, as also 

 Pasiphsea norvegica, Sars. Pasiphwa cristata was taken with the trawl near the Fiji 

 Islands, and Pasiphsea amplidens is found near Japan, Pasiphsea acutifrons in the Strait 

 of Magellan, and its near ally Orphania tenuimana off the eastern coast of North 

 America. These species, together with Pasiphsea sarignyi, Leach, and Pasiphsea brevi- 

 rostns. Milne-Edwards, from unknown localities, are evidence of the rarity of the species 

 and the paucity of the individuals. They appear to be very extensively distributed in 

 depth, ranging from a few fathoms to over a mile and a half. A scarcity of specimens 

 may be due to our want of knowledge of the habits of the animal and the localities which 

 it most frequents. 



Pasiphsea cristata, n. sp. (PI. CXL. ; PI. CXLL fig. 1). 



Laterally compressed. Carapace one-fourth the length of the animal, measured from 

 the fi'ontal margin to the extremity of the telson ; dorsal surface rounded, not carinated ; 

 frontal margin not advanced to a rostrum between the ophthalmopoda, frontal region in 

 the median line elevated, with a laterally compressed triangular crest. Orbits imper- 

 fectly excavate and defined by an outer obtusely pointed canthus, beneath which, but 

 less advanced, is the rounded projection that represents the first antennal tooth, and 

 still more retiring is a distinct and well-formed tooth that corresponds with the second 

 pair of antennse, beneath which the frontal margin still recedes and unites with the 

 lateral margin, forming an obtuse angle, from which posteriorly the sides of the carapace 

 gradually deepen. 



Pleon dorsally smooth, rounded, and laterally compressed ; first somite shorter than 

 the succeeding, second and three following subequal, and sixth much longer than the 

 preceding. Telson about half the length of the sixth somite. 



Ophthalmopoda moderately broad. 



First pair of antennas having a stylocerite that is sharply pointed, and nearly as long 



1 Mr. John Murray has recently (1887) dredged large numbers of Pasiphsea sivado, of all sizes, in Loch Fyne, Loch 

 Etive, Loch Aber, and Loch Carr >n, in the west of Scotland, in depths of from 50 to 100 fathoms, on a muddy bottom. 

 Their stomachs contained fine mud. 



(ZOOL. CHALL. EXP. — PART LII. — 1887.) Fff 109 



