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



supports a short mastigobranchia of great tenuity, fringed with long slender hairs ; the 

 basis carries a long ecphysis, the first joint of which reaches nearly to the extremity of the 

 ischium, and terminates in a multiarticulate extremity that is tipped with one or two 

 hairs, and reaches to the propodos ; the ischium is short ; the meros is long and some- 

 what narrowing to the carpos ; the carpos, propodos, and dactylos are subequal, the 

 propodos being somewhat the larger of the three, and is fringed on the inner and outer 

 margins with long hairs, among which on the inner side are a few spines, armed with short, 

 stout teeth ; the dactylos terminates in four or five short, stiff, simple, spine-like hairs. 



The second pair of gnathopoda (fig. li) is long, pediform, and seven-jointed. The coxa 

 supports a short and delicate mastigobranchia, a podobranchial plume, and two ar,thro- 

 branchia; ; the basis carries a slender ecphysis that is about half the length of the 

 gnathopod, reaching to about the extremity of the meros ; the first joint is single, long 

 and slender, reaching to three parts the length of the ischium ; the second is multi- 

 articulate, and terminates in a few long hairs ; the ischium is long and has its margins 

 parallel, the inner being thickly fringed with long simple hairs, beneath which is a 

 row of small cusps ; the meros is shorter than the ischium, but is formed as a continua- 

 tion of it, and the inner margin, which is smooth, has a fringe of long hairs ; the carpos 

 is about the same length as the meros, but is slightly more robust and fringed on 

 the inner side with long hairs ; the propodos is a little shorter than the carpos, and 

 the dactylos is shorter than the propodos ; both are fringed on the inner side with 

 long slender hairs interspersed among which are others that are strong and fringed with 

 spines. 



The first pah* of pereiopoda is long, moderately robust, and chelate. The coxa is short, 

 and supports a mastigobranchia, a podobranchia, and two arthrobranchiae, all of which are 

 very short and delicate ; the basis is small, and visible only on the inner and lower 

 surfaces ; the ischium is robust and short, and articulates continuously with the meros, 

 which has the outer and inner margins nearly parallel, the surface is granulated with 

 small tubercles and armed with a strong tooth on the upper and lower angles of the 

 distal extremity ; the carpos is about half the length of the meros, and is armed at the 

 upper distal angle with a sharp anteriorly-pointed tooth ; the propodos is long and 

 narrow ; and the pollex, which is half the length of the palm, is about the same length 

 as the dactylos, and antagonises it throughout its entire length, the apices overlapping 

 each other. 



The second pair of pereiopoda is more slender and feeble, and about a third shorter 

 than the first. The coxa supports a small mastigobranchia, a podobranchia, and two 

 arthrobranchiae ; the basis, unlike that of the first pair, forms a distinct but short joint ; 

 the ischium is considerably longer though still short, and the meros is three times its 

 length ; the carpos is long and slender ; the propodos is longer than the carpos, and has 

 its margins parallel, the lower being produced anteriorly into a sharp, straight pollex, 



