ISOPODA. 47 



A larger specimen. 119 mm. long, is a male, ]>ut this was dead when found, and, besides 

 .some injury, its inside had heen almost completely eaten out. On the anterior border 

 of the first segment of the metasome are a pair of penial filaments ; these are eylindrical, 

 about 5 mm. long, and terminate in an obli<jue orifice surrounded by a fringe of stiflF 

 .setae. A further sexual character is the long, slender, grooved filament connected, at 

 its base only, with the endopodites of the second pair of pleopoda. It is half as long 

 again as its endopodite. 



The first antenna arise rather close to the middle line, and compri.se a peduncle of 

 three joints ; the first two are subequal in length, and the third is nearly as long as the 

 first two together. The first is slightly contracted in the middle, and has a group of 

 stout .setfe at its inner distal extremity ; the second has a small group about the 

 middle of its ventral border, as well as a distal fringe, which is, however, irregular, 

 being most accentuated ventrally. The third joint Ls more slender, swollen, and setose 

 di.stally. The fiagellum is not as hmg as the third joint of the peduncle ; it consists of 

 a .single joint, strongly curved near the proximal end, and has a baud of fine setae 

 running along its outer border. 



The second antenna arises immediately outside the first ; the peduncle is five- 

 jointed. The first joint is extremely short, the next two are subequal in size, the 

 second having a strongly developed distal fringe ventrolaterally, and the third has a 

 ventral mass of setae rather than a fringe ; the fourth joint is a little longer than the 

 preceding, and, like it, widens distally ; it has a well-developed donsal distal fringe and 

 a mass ventrally which is separable into two groups ; the fifth joint is nearly as long 

 as the third and fourth together ; it carries along the distal half of the ventral margin 

 four groups of setae, besides a dorsal and ventral distal fringe. The fiagellum is multi- 

 articulate, and half as long again as the peduncle. 



The buccal ma.ss is very prominent ; the supporting plate in front bears three 

 tubercles, of which the median is very prominent. The epistome is an irregularly 

 ovoid plate with a raised edge, and cleft in the middle. 



The mandible is large and powerful, devoid of a palp ; the cutting edge of that on 

 the left side is strongly cohjured, and overlaps that of the right 



The first pair of maxillae (fig. 2) consist of the two normal lobes, the inner one 

 considerably smaller and weaker than the other. The inner one terminates with three 

 rather long and strong seta; and .several others, much weaker ; very minute seta) occur 

 on both faces of the joint The outer lobe, at least twice the length and breadtii of the 

 inner, has eight strong spines distally, and its outer border is fringed with minute .setae. 



The second pair of maxillic (fig. 3) are broad, if thin. The inner lobe is constricted 

 about its middle, and then forms an ovoitl enlargement The inner and distal border 

 of this is furnished with long slender .setaj ; the two outer lobes are very nearly equal 

 in size; they are rounded di.stally and provided with long slender setae; fine setae 

 occur on the outer border and the base of the external lobe. 



The maxillipcd (fig. 4) is large and strong. The basal joint is broad and stout, the 



