REPORT ON THE CRUSTACEA MACRURA. 51 



propodos; the sides are curved, gradually converging to a point, and covered plentifully 

 with long hairs. 



The first pair of pereiopoda is asymmetrical both in size and form. That on the 

 right side has a short ischium, convex on the outer side, and flat or concave on the inner. 

 The upper ridge is produced into a backwardly-directed process that overlaps and plays 

 round the neck of an anteriorly directed nodule on the basis (PL VI. M"). The 

 meros is flattened vertically, and has but two margins, except near the carpal joint, 

 where it is thickened and has three ; the carpos is short and nodular, and articulates on the 

 infero-exterior angle of the meros ; the propodos articulates on the infero-anterior angle of 

 the carpos ; it consists of a double ovate mass, placed side by side, one division of which 

 only (the upper or anterior) articulates with the carpos, the other is rounded posteriorly; a 

 deep constriction on either side anteriorly separates this body of the propodos from the 

 digital extremity, which is prolonged into a very long, slender pollex, flattened vertically 

 to the plane or surface of the propodos ; it is curved at the distal extremity into a long 

 and slender sharp tooth, and armed in its entire length with a series of long, slender 

 teeth, intermingled with shorter ones of the same character. These are regularly planted, 

 some directed obliquely inwards, the others outwards, on the entire length of the pollex. 

 The dactylos closely resembles the pollex both in form and size, and when the two are 

 compressed together, the long, slender teeth are interlocked together very regularly. On 

 the left side the carpos is short, but less bulbous than on the right. The propodos is 

 narrow and long, having the margins parallel, the under side smooth, and the upper 

 surface minutely spinous as far as the base of the pollex, which is but a little longer than 

 the palm ; the dactylos resembles the pollex closely, and is a modified type of the right 

 appendage ; it is smooth on the outer side, and fringed with a series of delicate teeth, 

 that interlock with similar ones on the inner margin of the pollex. 



The second pair of pereiopoda is nearly as long as the first, not including the 

 dactylos, but is much more slender and chelate. The propodos and carpos are subequal, 

 and the dactylos and pollex are short, not being half the length of the propodos, which 

 latter is not wider than the carpos, and has the inferior and superior margins parallel. 



The third pair of pereiopoda very closely resembles the second, but is smaller as a 

 whole. 



The fourth pair is still shorter, and differs chiefly in being mono-dactyle, the pollex 

 being absent, or existing only as an unimportant angle of the propodos, much imbedded 

 in fur. 



The fifth pair equals the preceding in size and length, but terminates in a minute 

 and perfect chela buried in a thick brush of fur. 



The first pair of pleopoda is small, slender, and terminates in a single hairless 

 branch. 



The second and three succeeding pairs are short and robust, and carry two narrow 



