ASTRICLYPEUS MANNI. 539 



Astriclypeus Manni 



! Astriclypeus Manni Veurill, 1867, Notes Rail. p. 311. 



PI XIII d . f. 2-4. 



The test is extremely stout ; the outline from above is circular, somewhat 

 truncated on the posterior edge. The test is depressed, regularly conical, 

 with rounded apex, sloping uniformly from the vertex to the thin edge ; the 

 vertex is slightly anterior to the apical system, which is large, as in Encope, 

 with the two posterior genital pores farther apart than the anterior. The 

 petals are slightly unequal ; the odd anterior is the longest ; the anterior 

 pair are only slightly longer than the posterior, and the interporiferous spaces 

 of nearly the same width ; the poriferous zones are broad, broadest at the 

 extremity of the petals, which appear abruptly truncated ; the petals are 

 nearly closed at the extremity ; the inner pore is large, round, connected by 

 a sharp furrow with the minute outer pore ; the furrows are in close prox- 

 imity ; the poriferous zones are not so broad as the interporiferous spaces. In 

 large specimens measuring 121 mm , long, diam., the lunules are oblong, wide ; 

 the posterior pair slightly larger than the others. In smaller specimens the lu- 

 nules were proportionally longer, much narrower, and the difference in length 

 between the odd anterior petal and the anterior pair quite marked ; they, in 

 turn, being considerably longer than the posterior pair. The summit of the 

 test was also more conical, not flattened, as in the largest and oldest speci- 

 mens examined. The lower surface is flat ; the actinostome rather nearer 

 the posterior edge than the anterior edge. Shallow grooves extend from the 

 lunules to the actinostome ; they carry larger tubercles than those on the 

 rest of the actinal side ; similar tubercles also exist round the anal opening, 

 which is smaller than the mouth, of irregular outline, about half-way between 

 the posterior edge and the mouth. The ambulacral furrow, after diverging, 

 runs nearly parallel on both sides of the lunules, sending out from four to 

 five branches, which in their turn send off a few irregular spokes into the 

 broad interambulacral spaces. The actinal surface, except as mentioned 

 above, is covered by a very uniform tuberculation, slightly more crowded in 

 the median interambulacra towards the edge of the test, similar to the tu- 

 berculation of the abactinal part of the test, which extends also over the 

 whole of the ambulacral rosette. 



On some of the specimens preserved in the Liverpool Museum the spines 

 w r ere still retained on the upper side ; they are extremely clavate at the 

 extremity ; on the lower side, according to the size of the tuberculation, 



