ASTROPIIYTON COSTOSUM. 



193 



First fork to second 8"""- 



Second •■ " tliiiil 11" 



Tliinl '• •• louitli, M " 



Fourth " ■• lifili, II" 



Fifth •• •• si.\th II" 



Sixth '• '• scvcnti IG " 



Seventh •' " eighth, IG " 



P:ighth " *' ninth, IG '• 



Nintii " " tentli IG •' 



Tenth " " eleventh 11) •' 



Eleventh " " twelfth 18 " 



Twelfth " " thirteentii 19 " 



Thirteenth " " foiirteentli, .... 20 " 



Fourteentli " " fifteenth, 17 " 



Fifteenth " '• sixteenth 17 *' 



Sixteenth " " seventeenth, . . . . 18 " 



Seventeentli " " eightei^nth, . , . . 21 ' 



Eighteenth ' " nineteentli, . . . . 18 "■ 



Nineteenth " " twentieth 18 '• 



Twentieth '• " twenty-lirst, . . . . 18 " 



Twenty-first '' '' twenty -seconil, . . . 17 " 



Twentj-sei'ond " '• twenty-third, . . . 15 " 



Twenty-third " " twenty-fourth, . . . 10 " 



Twenty-fourth '• '• twenty-fifth, . . IG " 



Twenty-fifth " '• twenty-sixth, . . . 20 '' 



Twenty-sixth " '• twenty-sevent'i. . . 13 " 



Twenty-seventh •' " twenty -eighth. . . . 12 '' 



Twenty-eighth " " twenty-ninth, . . , 12 " 



Twenty-ninth " •' thirtieth, . . . . 11 " 



Thirt'eth " " tliirty-first 10 " 



Thirty-first " " thirty-second, ... 8 " 



Thirty -second, •' " end, 11" 



Total length, 489'"™- 



Distance from outer side of maclreporic shield to inner jioints of teeth, 

 to that between outer corners of mouth-slits, 10 : 9. Teeth, tooth- 

 papilhe, and mouth-papilla) sharp, conical, of different sizes ; about 

 eight, which occupy the place of teeth, are the largest, and atttiin the 

 length of 2.8°""- ; those which represent the inner mouth-papilla? are 

 smallest ; the outer moutli-])apilhT3 extend quite to the outer corner of 

 the mouth-slit. Madreporic shield irregular oval, broader than h^ig, 

 rather indistinct ; placed at the inner angle of the interbrachial space. 

 Arms covered above, below, and on the sides by a close, fine, smooth 

 coat of microscopic grains. Below and on the sides the joints are 

 plainly indicated by cross lines. On the upper side runs a distinct, 

 longitudinal, sunken line ; here also are scattered round spots, which, 

 under the microscope, appear a little raised, and are made up of con- 

 centric rings of oblong grains. On the tip Ijranches most of the grains 

 are brought together to form a douljle vertical row of grains, which 



