34 PROCEEDINGS OF THE NATIONAL MUSEUM vol. S6 



lateral expansions carried below the head and mouth parts and much 

 below the ventral line of the adjacent segments; anterior margin 

 straight to below the eyes, then carried forward and downward in a 

 broad, even curve to tlie rounded posterior corner, the curved margin 

 bordered by a fine raised rim; median surface smooth and shining, 

 lateral surface slightly granular. 



Segments 2, 3, and 4 narrowing caudad ; segments 2 and 3 smooth 

 above, finely striate low on the sides; segment 4 longer than 2 or 3, 

 with dorsal crests of smaller size but in the same position as those 

 on the ensuing segments, and with a small lateral tubercle in the 

 position of the poriferous carinae. 



Succeeding segments gradually broadening, the anterior sub- 

 segments considerably exposed, densely and minutely reticulated, 

 the posterior portion constricted and coarsely and regularly fluted in 

 front of the transverse suture; flutings on the lower half of the 

 body usually corresponding to the crests of the posterior subseg- 

 ment, but the dorsal flutings somewhat more numerous than the 

 crests. Posterior subsegments with about 12 crests between the 

 poriferous carinae; beginning at the middle of the dorsum there is 

 a small crest, then a distinctly larger one, then 3 to 6 smaller crests, 

 which are sometimes quite variable in size and length but are more 

 prominent near the middle of the segment and abruptly lower and 

 narrower behind; the large submedian crests often thickened in 

 front, especially at the anterior end of the body. Lateral carinae 

 with a very large poriferous prominence in front, the carina abruptly 

 interrupted behind it but again raised into a large conic tubercle at 

 the posterior margin. Pores beginning on segment 5 and ending 

 on the antepenultimate segment, opening outward from the smooth 

 oval surface of the pore prominence. Sides below pores with 10 to 

 12 distinct crests separated by striations; a prominent oblique crest 

 near the legs surrounding a slightly depressed area around the basal 

 joints of the legs. 



Posterior segments narrowed gradually, with dorsal and lateral 

 crests reduced; penultimate segment very short, with sculpturing 

 reduced and pores lacking. 



Last segment rather long, with an elongate median thickening or 

 ridge continued as a definite mucro beyond the anal valves, surface 

 otherwise smooth. 



Anal valves facing obliquely downward, very prominent and in- 

 flated, the margins meeting in a deep groove, surface smooth and 

 shining. Preanal scale short and very broad, the posterior margin 

 nearly straight across, somewhat thickened and prominent, with two 

 minute submedian setiferous punctations. 



