52 ME. P. H. CABPENTEB ON THE GENUS ACTINOMETBA. 



gradually diminishes to the pinnules of the fourth and fifth brachials, -which are the shortest on the 

 whole arm. From the sixth brachial onwards the pinnules are long and stout, gradually increasing in 

 length and thickness to near the middle of the arm ; the thickness is greatest in the short posterior arms, 

 in which both length and thickness rapidly decrease from the middle to the end of the arm, while in the 

 long anterior arms the thickness slowly diminishes and the length slightly increases, so that the terminal 

 pinnules are long and slender. 



Comb. The last six or eight segments of the distichal, palmar, and first eight or ten brachial pinnules 

 have the outer ventral margin of each calcareous segment produced into a small lancet-shaped process 

 which bends over towards the ventral side, so that the end of the pinnule has a comb-like appearance. 

 Many of the other pinnules till near the end of the arm have similar processes upon their four or five 

 terminal segments. 



Disk. Mouth excentric and interradial ; posterior ambulacra very indistinct, and often nearly obli- 

 terated. Small calcareous concretions occasionally present in the neighbourhood of the peristome and 

 anal tube. 



Colour. Yellowish brown to dark brown. 



Diameter. About 20 centimetres. 



Locality. Bohol. 



The following are the points in which the varieties differ from the type as described above : — 



Variety 1. 



Cirrhi. 25, of 13-15 segments, with terminal claw ; spines on dorsal face of terminal segments not very 

 distinct, but the segments are laterally compressed. 



Radials. Second radials completely united with one another in pairs. 



Arms. 20. 



Syzygial interval. Usually 3, but varying from 1-10 segments ; generally to >3. 



Comb. From 2nd distichal to 6th brachial pinnules, and then, at intervals, to about 20th brachial 

 but no further. 



The basal pinnules of the arms have a faint dorsal keel, and the distal ends of their segments are 

 rather wider than the proximal ends. 



Diameter. 105 millims. 



Colour. Greyish brown. 



Locality. Ubay. 



Variety 2. 



Centrodorsal piece. Small, but rather thick. 



Cirrhi. 10, of 11 or 12 segments, with a terminal claw; the fourth and fifth are longest; the spines 

 on the dorsal border begin from the middle segments, and the opposing process on the penultimate 

 segment is well marked. 



Radials. Second radials only incompletely united ; second and third very convex, and much higher 

 than the first ; median dorsal line of skeleton marked by a white line with dark borders, which is lost 

 about the middle of the arms. 



Arms. 29. 



Syzygial interval. Usually 3, but varying from 1-10 segments; generally to >3. 



Comb. Limited to distichal, palmar, and first five brachial pinnules ; those of the Gth and next 

 succeeding brachials have a dorsal keel, and the distal ends of their segments are much wider than the 

 proximal ones. 



Colour. Greyish brown. 



Locality. Cabulan. 



