ME. P. H. CAEPENTEE ON THE GENUS ACTINOMETEA. 29 



irregularity. As a general rule all the individuals of a species agree in the presence or 

 absence of distichals and palmars. 



9. In Act. Bennettii there are more than 70 arms ; but all the axillarics are like the 

 iirst one (distichal), and not different from it, as in Act. multifida. According to 

 Miiller ', every fourth segment is an axillary without a syzygium ; but Bohlsche'" has found 

 this to be incorrect. There are, indeed, four segments between every two points of division ; 

 but the last two are imited by a syzygium ; so that the formula becomes three distichals, 

 palmars, &c., of which the axillary has a syzygium. Bohlsche's figure of the disk of his 

 sjiecimen is noteworthy; for though five groove-trunks leave the excentric peristome, as in 

 Alecto, yet their distribution to tlie arms is not by any means symmetrical, so that he 

 seems to have decided upon calling it Actinometra. Miiller named it simply Comatiila. 



(§ 20) In the above scheme are included all the species of Comatula which have been, 

 determined by myself or by others ^, as far as I know, to belong to the type Actinometra. 

 Fourteen of these were known to Miiller ; and of the remaining 23 species described by 

 him I have been able to refer 16 to Antedon, viz. : — 



Ant. adeona. Ant. macrocnema. Ant. phalangiuin. 



Ant. articulata. Ant. Milberti. Ant. Philiberti. 



Ant. carinata. Ant. Milleri. Ant. Reynaudii. 



Ant. Eschrichtii. Ant. palmata. Ant. rosacea. 



Ant. Jacquinoti. Ant. petasus. Ant. Sarsii. 



Ant. Savignii. 



To these must be added 



Ant. armata, Pourt. Ant. cubensis, Pourt. Ant. Hagenii, Pourt. 



Ant. bicolor, Mus. Paris. A7it. dividua, Mus. Paris. Ant. poly actinis, Mus. Paris. 



Ant. celtica, Barrett. Ant. Dubenii, Bolsche. Ant. rubiginosa, Pourt. 



The following list contains the seven remaining species of Comatula described by 

 Miiller which I have not been able to examine, and of which I know no descriptions from 

 wliich it is possible to obtain any information as to the position of the mouth or 

 tlie character of tlie oral pinnules. 



C. Cumingii. C. elongata. C. jlagellata. 



C.japonica. C. novee Guinea. C. tessellata, 



and C. timorensis. To wliich must be added C. brevipinna, Pourt. 



III. External Characters of Act. poltmorpha, and Specific Diagnosis of the Type. 

 (§ 21) In Act. -polymorpha, as in all Actinometi^ce, the mouth (PI. I. figs. 6-16, m) 



' ' Gatfcung Comatula,' p. 28. 



- " Ui'bsr Actinometra Bennettii und eiuc neuc Comatula-Ait (Antedon Diihenii)," AViegm. Archiv, 18GG, i. p. 90. 



' Dr. Liitkcn has named several new species of Actinometra besides Act. rohusta — for example, Act. tenax and 

 Act. trachygaster. But his descriptions have not, as far as I know, boon published ; and I have had no opportunity of 

 examining any specimens of his new species except Act. rohusta ; so that I am unable to place them in the classi- 

 lication given in the previous section. 



Grube has described a new Actinometra from Borneo, and two new species of what he calls Comatula. His de- 

 scriptions (Jahresber. d. Schlesisch. Gesellsch. 1875, Nat.-Hist. Sect. pp. 54, 55) are, unfortunately for me, not to be 

 obtained iu this country. 



