512 THE VOYAGE OF H.M.S. CHALLENGER. 



like ecphysis arises, which gradually tapers to the extremity ; it is hirsute, more especially 

 near the base ; the ischium is also short and broad ; the meros is longer and tapers 

 slightly towards the distal extremity, where it articulates with the earpos, which is short, 

 narrow at the base, and broad at its distal margin, where it articulates with the propodos ; 

 the latter is long and ovate, to receive the dactylos, which is short and broad and fills 

 up the deficiency in the ovate form of the propodos. The distal margin of the dactylos 

 and the outer margin of the propodos are thickly fringed with stiff hairs interspersed 

 with strong spines. 



The second pair of gnathopoda (i) is long, robust, and pediform, it consists of only 

 four distinct joints, the homologues of which are difficult to determine, but naming those 

 that remain according to their relative position in the limb, the coxa and the basis are 

 short, the latter, the ischium and meros are united into one long joint, which is concave 

 below and excavate on the upper surface to allow space for the several preceding 

 appendages that surround the mouth, and supports a slender and lash-like ecj)hysis, 

 which articulates immediately beyond the coxal articulation. The next joint, which may 

 be the earpos, articulates at a considerably oblique angle with the preceding ; it increases 

 in size slightly towards the distal extremity. The upper surface is transversely rounded, 

 the lower excavate, and the internal perpendicular, the two latter being thickly matted 

 with short hairs ; the outer margin is fringed with few hairs and some large strong spines. 

 The terminal joint resembles the dactylos of a true pediform appendage, and is probably 

 the propodos and dactylos united and compressed ; it gradually tapers to the unguiculated 

 sharp pointed extremity. The inner, under, and outer sides are studded with strong 

 spines that articulate in thick marginal sockets. 



The first pair of pereiopoda (k) is robust but not very long, being only subequal to 

 the second pair of gnathopoda. The coxa is short and broad ; the basis is short and 

 firmly fused with the ischium, which is anteriorly produced on the inner side to a strong 

 sharp process or tooth, the outer side is oblique and articulates for nearly its entire 

 length with the base of the meros, with which it has but little free movement and that 

 only in one direction ; the meros is long and slightly tapering to the distal extremity ; 

 the earpos articulates at the extremity of the meros, and bends suddenly at a right 

 angle ; the propodos is ovate, gradually narrowing to the distal extremity, where it 

 articulates with a sharp pointed, curved, cylindrical dactylos, which, when closed, 

 impinges against the under, slightly flattened, surface of the propodos. The under and 

 upper margins of the palm of the propodos are defined by several fasciculi of short hairs. 



The second pair of pereiopoda (I) is long, slender and feeble. The coxa and basis are 

 short ; the ischium is long and traversed on the lower and inner side by a deep thin ridge, 

 thus providing on the upper surface a concave space in which the distal extremity of the 

 reflexed earpos lies protected when folded and at rest ; the meros is as long as the ischium, 

 and cylindrical ; the earpos is as long as the ischium and meros together and multi- 



