REPORT ON THE CRUSTACEA MACRURA. 743 



the length of the next succeeding joint, which consists most probably of the ischium 

 and meros united, and is curved to leave space for the oral appendages. The next joint 

 is long and narrow, and probably represents the carpos, and the terminal joint is long, 

 slender, and straight, obliquely truncate, and laterally fringed with a soft fur of short hair. 



The first and second pairs of pereiopoda are chelate, the anterior pair is slightly 

 shorter than the succeeding, and a little more robust ; the carpos is long, nearly as long 

 as the propodos, which is not larger in diameter, and terminates in two closehy impinging 

 fingers, of which the movable dactylos is more curved than the fixed pollex. The third, 

 fourth, and fifth pairs of pereiopoda are simple and rather short, being scarcely longer 

 than the first two pairs ; the ischium and meros are rather stout, and the carpos is long ; 

 the third and fourth pairs terminate in a long and slender dactylos, while in the fifth 

 pair it is short and supported by a brush of hair. All the pereiopoda, including the 

 chelate pairs, and also the gnathopoda, carry a slender basecphysis that lessens in length 

 on each posteriorly, but is never rudimentary, and all excepting the posterior pair carry 

 a mastigobranchial appendage, which, though small, is sufficiently long to penetrate to 

 about half their length between the branchial plumes, and fulfil, we may assume, some 

 efficient duty connected with respiration. 



The pleopoda are biramose, having a short basal joint and narrow, subfoliaceous, 

 flexible branches ; the inner in the female carries a long stylamblys tipped with a 

 bundle of cincinnuli, except in the case of the first pair, which has the inner ramus 

 reduced to a rudimentary condition and thickly fringed with plumose hairs, and without 

 a stylamblys such as is present in Acanthephyra armata. The posterior pair of pleo- 

 poda, which forms the lateral plates of the rhipidura, is narrow and subequal in length 

 to the telson, and the outer angle of the diseresis is armed with a tooth and small 

 spinule. 



The eggs are ovate and numerous, and of moderate dimensions. 



The branch ias are generic in character. 



Observations. — This species appears to be both abundant and widely distributed ; it 

 was taken by the Challenger at eleven stations, more or less distant from one another, 

 — in the Atlantic and Pacific Oceans, as far north as Japan, and as far south as New 

 Zealand. It is a more perfect representative of the genus than Acanthephyra armata. 

 Its bathymetrical range is also great, since it has been taken at a distance of from less 

 than half a mile to about three miles from the surface of the ocean. It appears to be 

 very prolific also, since some of the females that were captured carry a large number of 

 small eggs. 



The specimen taken at Station 318 in the South Atlantic Ocean is a variety that 

 approximates somewhat both in size and features to Acanthephyra acanthitelsonis, which 

 was taken in Mid Atlantic near the equator. It differs from the typical form in being 

 larger, in having only three teeth on the lower margin of the rostrum, two of which 



