1895. PROCEEDINGS OF THE NATIONAL MUSEUM. 103 



regularly curved, anteriorly diverging from the margin. Around the 

 entire segment is a well-defined, raised margin, broadest in front and 

 broken into small, irregular teeth behind. 



Second segment somewhat broader and much shorter than the first, 

 subsimilar in general shape except that it is deeply and broadly eniar- 

 ginate in front instead of convex. There are three transverse rows, 

 each of six tubercles, the two middle ones of the posterior row very 

 close together, coalesced, forming a large subpyramidal a[)ically bifid 

 process. The middle tubercles of the second row are also close together, 

 somewhat enlarged and forming a part of the large process, as do also 

 the pair of tubercles of the third row neighboring to the middle ones. 

 The raised margin of the segment is carried up on the process, leaving 

 a somewhat concave posterior face below it. 



Third segment slightly longer than the second, the process consider- 

 ably larger, the two middle tubercles of the posterior row forming the 

 apex, the next pair projecting about halfway down the sides. 



Fourth segment slightly longer than the third, the process somewhat 

 smaller, about as high as that of the second segment, but broader. 



Fifth segment noticeably longer than the fourth, the process entirely 

 disappeared, the four middle tubercles of the last row equal and at 

 equal distances, with an evident transverse sulcus in front. All the 

 tubercles of this segment located in subquadrate or hexagonal areas 

 more or less defined by furrows. A tendency to areation is also api^ar- 

 ent in the i^ receding segments, but the difference between this and 

 the fourth segment is very abrupt. 



Subsequent segments similar; the tubercles becoming more numer- 

 ous (8-12 in a row) and less elevated in middle segments, and again 

 more prominent on the latter segments, especially along the posterior 

 margin. 



Penultimate segment with a row of ten sharp, conic, papilliform 

 tubercles projecting upward and backward from its posterior margin. 

 Surface of this and preceding segments more coarsely uneven than on 

 middle segments, but still shining. 



Lateral carinas with three rather obscure teeth on segments 1-5; after 

 that with three or four teeth. Intramarginal ridge gradually closer 

 to the margin, until it becomes nearly obsolete on segments 11 and 14. 

 On poriferous segments, however, it remains distinct, more or less arc- 

 uate opposite the pore; posterior corner of carina thickened, especially 

 on posterior segments. 



Eepugnatorial pores on anterior segments located slightly behind 

 the middle of the segment, nearer to the ridge than to the margin; on 

 posterior segments the pores are gradually farther back, and in a deeper 

 and deeper depression midway between the ridge and lateral margin. 



Below the carinte the segments are irregularly rugulose, becom- 

 ing granular, coarsely tuberculate along both margins of the subseg- 

 ment below; prominent above the insertion of the legs, and with two 

 large long-pointed tuberculate processes, the anterior larger, directed 



