A MONOGRAPH OF THE EXISTING CRINOIDS 645 



Of the 3 specimens from Friedrich-Wilhclms-IIaven, New Guinea, 2 are of 

 medium size, with about 20 arms, and 1 is rather larger, with about 27 arms. All 3 

 have a few cirri remaining. 



The Challenger specimen from the Admiralty Islands in 29-46 meters was 

 described by Carpenter as a new species under the name of Actinometra simplex. 

 According to him, the characters are as follows: 



The centrodorsal is a thin disk bearing marginal cirri. 



The cirri are about XV, 14-17. A few of the cirrus segments are longer than 

 broad. 



The radials and portions of the IBr! are concealed by the centrodorsal. The 

 IBri are partly united laterally. The IIBr series are 2. 



The 18 arms average 45 mm. in length. The anterior arms are composed of 100 

 brachials, while the posterior arms consist of 45 brachials. Some of the posterior 

 arms are grooveless. The brachials are short, subtriangiilar, and slightly overlap- 

 ping, becoming more elongated at the ends of the anterior arms. 



Syzygies occur between brachials 3 + 4, again at about brachials 11 + 12, and 

 distally at intervals of from 3 to 5 muscular articulations. 



PI is about 7 mm. long, and the following pinnules decrease in length to those 

 on the fifth and sixth brachials, afterwards increasing again. The terminal pinnules 

 of the anterior arms are very long and slender, those of the posterior arms being 

 shorter and stouter. The first 4 pinnules on each side have a small terminal comb 

 which is found at intervals until near the ends of the arms. 



The disk is 8 mm. in diameter and bears a few calcareous granules. The mouth 

 is interradial. 



The color in alcohol is dull green dorsally, deep brown ventrally. 



Carpenter said that this (simplex] is a curious little species which differs alto- 

 gether from elongata in the shortness of the brachials and in the concealment of the 

 radials. It has many resemblances to parvicirra, but is separated from that type 

 by the smaller number of elements in the IIBr series. It presents, however, the same 

 difference in the length of the anterior and posterior arms as occurs both in parvicirra 

 and in elongata; but some of the posterior arms are ungrooved, which is not the case 

 in elongata. 



The specimen from Pitilu has 25 arms, of which the longest are 120 mm. in length. 

 Eight of the IIBr series are 2 and 2 are 4 (3 + 4). Four of the IIIBr series are 4 

 (3 + 4) and 1 is 2. Two of the IIIBr series are developed externally and 3 are devel- 

 oped internally. 



The example from Ekalin has 31 arms. All of the IIBr series and 2 of the IIIBr 

 series are 2. The cirri are IV, 10-11, 6.5 mm. long. 



The specimen from New Caledonia has 28 arms. 



The specimen from the New Hebrides is typical. 



The specimen in the Hamburg Museum labeled "Tonga and Fiji" is of medium 

 size. 



The example from Vanua Mbalavu, Fiji, is typical, with 20 arms. Of the IIBr 

 series, 1 is 2 and 9 are 4 (3 + 4). 



Of the 3 specimens from Suva Reef, 1 has 21 arms. In another, only 1 of the 

 IIBr series is 4 (3 + 4), the others being 2. 



