[59] 



DECAPODA FROM ALBATEOSS DREDGINGS. 



403 



Male. — The form and areolation of tbe carapax are very nearly as iu 

 the last species, but the rostrum terminates iu an acicular tip longer 

 than in that species. The eye-stalks are considerably longer than iu 

 the last species, and the eyes are much larger, the diameter being about 

 a ninth of the length of the carapax, while iu the last species it is uot 

 more than a thirteenth. The antennulte, antennae, and oral appendages 

 are essentially as iu the last species; and, excepting the dactyli of the 

 fourth and fifth pairs, which are broken and in part wanting, the same 

 is true of the perteopods. 



The form of all the somites of the pleon and the telsou are very uearly 

 as iu the last species, but the lamellae of the uropods are apparently 

 slightly broader iu proportion. The sexual appendages (petasma) of 

 the first pleopods (Plate X, Fig. ti) are larger and conspicuously dif- 

 ferent in form from those of the last species, though essentially the 

 same in general plan of structure. The broad, oval process (a) over the 

 narrow base of attachment is much smaller; the inferior chitinous edge 

 of the middle part is complicated iu form, being divided into three ir- 

 regular lobes, the outer of which projects in an obtuse point, and is sep- 

 arated from the others by a deep and irregular sinus, while the other 

 lobes are broad, truncated, the outer longer than the inner, and sep- 

 arated from it by a small, uarrow sinus; the iuner of these lobes is sep- 

 arated by a broad, rounded sinus from a large, broad lobe which arises 

 from the anterior side and projects over the membranous inner part of 

 the appendage. This last lobe (b) is very much larger and proportion- 

 ally broader than the corresponding lobe in the last species, and has a 

 small lobule on the inferior side near the base. The two plates at the 

 base of the inner ramus of the second pleopod are of uearly the same 

 form as in the last species, but somewhat larger. There are also two 

 small ijrocesses on the base of the outer ramus, but the proximal one is 

 very small, low, and inconspicuous, while the distal is very much larger, 

 conspicuous, lamellar, and ovate, with the tip directed downward away 

 from the other process. 



Measurements, in millimeters, of the single specimen, from Station 

 2003, March 23, north lat. 37° IG' 30", west long. 74° 20' 36", G40 fath- 

 oms, are given in the second column of the following table, and similar 

 measurements of A. elegans iu the first column. 



Station 



Sex 



Length from tip of rostrnm to tip of telson 



l.enfith of carapax, including rostrum 



Length of rostixun 



Hi;ilit of carapax 



Breadth of carapax 



Length of eye-stalk ami eye 



Greatest di^imeter of eye 



Length of antenual scale 



Breadth of antennal scale 



A. elegans. A. valens. 



2083 



