MARINE ISOPODA OF NEW ENGLAND, ETC. 389 



little longer than the second; the seventh about as long as the second. 

 The last segment, and in a less degree the sixth and fifth segments, 

 have their posterior margins excavated along the back; all have their 

 lateral angles rounded, although the angles of the seventh segment are 

 but slightly so. The epimera are short and pointed; those belonging 

 to the second and third segments are larger than the following ones, 

 and are applied directly to the lateral margin of the segments; the 

 posterior four pairs of epimera are shorter and smaller, and are separated 

 from the lateral borders of the segment by a fold of the integument 

 cutting off a portion of the anterior lateral angle and increasing in size 

 to the last segment. 



The first three pairs of legs are alike, distinctly ancoral and directed 

 forward. In each the basis is much the longest segment; the ischium 

 is strongly flexed upon it; the merus is expanded distally around the 

 base of the carpus and bears a few bristles at the outer angle; the 

 carpus is short, less than half as long as the propodus, and the dac- 

 tylus is strong and curved. The fourth pair of legs, like those that 

 follow, is directed backward; the basis is the longest segment and the 

 ischium is strongly flexed upon it and of more than half its length ; the 

 merus, carpus and propodns are each about two-thirds as long as the 

 ischium, and all four segments are armed distally with a whorl of spines 

 around the articulation with the succeeding segment; the dactylus is 

 slender, sharp and curved. The fifth pair of legs is longer than the 

 fourth by a little more than the length of the dactylus, the elongation 

 being in the segments from the ischium to the propodus inclusive. The 

 sixth pair is the longest, being, when extended, as long as the thorax 

 and pleon together. This elongation is confined also to the four seg- 

 ments above indicated, and of these the ischium is about as long as the 

 basis; the merus falls a little short of the ischium in length; the carpus 

 and propodus are of equal length, and are as long as the ischium ; all 

 these segments are slender and slightly curved, and are armed distally 

 and along their inner side with short spiuules. The dactylus is slender 

 and curved. The seventh pair of legs resembles the sixth but is shorter 

 by about half the length of the propodus. The fifth pair does not 

 attain the middle of the carpus of the sixth. 



The pleon is of less diameter than the last thoracic segment and 

 about as long as the last five thoracic segments. Its transverse diame- 

 ter increases slightly to the base of the last segment, where it is broad- 

 est; the fifth segment is a little longer than the preceding one, and 

 the last segment is of a broad ovate form, acuminate and ciliated at the 

 tip, truncated at the base and smooth above, except for a faint trans- 

 verse impression on each side near the base, and a still more faint im- 

 pressed median line toward the tip. The uropods attain the tip of the 

 telson but do not surpass it ; they have the basal segment oblique but 

 not produced at the inner angle, and bearing two elongate-elliptical 



