ECHINODERMATA. 



1 55 



adeon.T A. ,'• 



b 



inilberti A. ,'• 



b 



pimiiformis A. j- 



carponteri ....• A. -■ 



pumila A. — 



bidens A. — 



a 



loveni A. — 



x 



I 

 decipiens A. (.">), 



Antedon. 



roginic A. 2.(2)- 



articulata . 



A. 2.2- 



irregularia A. 3.(2)g- 



1 A Q ( 2 ) b 



Blegans A. 3. (Ti) - 



-Y-.-S 



A. 2.2. 



briareus* A. '3.2.(2) - . 



v 'a 



microdiscus A. 3.3.(3)-. 



AciINOMETRA. 



6olaris 



2 a 



intermedia A'R- •-• 



2 a 



robusta A'R— . r- 



2 D 



cuunngi A-- 



coppingeri 



jukesi 



A*. 



a 



parvieirra A'3.3. 



., -pd.br 

 (ab) 



alternans A'3.2.3.2.^- 



. . , /T) d.br a 



paucicirra Alt— •- 



multifida A'3.2.2.- 



'A'3.2.-- 



a 



■variabilis < A'3.3.-- 



.A'3.(2).(2) 



From the table of Antedon formulae some facts become at once 

 apparent : — 



(a) Tbere are six examples among the more than ten-rayed forms 

 in which the arms are not a regular multiple of ten — that is, not 20, 

 40, or 80 ; this is clear from the sign for the palmar or post-palmar 

 being in these cases placed within brackets. 



(/3) In all cases cirri are developed, and these are rarely very 

 numerous or very long. 



(y) In no case is the radial axillary a syzygy. 



A moment's inspection of the table of formula? for the Actino- 

 metrcp will reveal to the student a number of interesting facts : — 



(a) Three species have the same structural characters, and only 



* A study of this species is sufficient to show the advantage of Mr. Carpenter's 

 proposal to register the number of joints in each division over my proposal to 

 register rather the syzygies first of all, as A. briareus has no syzygies on the 

 palmare or succeeding joints where the arms divide again. 



