MR. P. H. CARPENTER OX THE GENUS ACTINOMETRA. 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 axillaries are like the 

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

 Miiller 1 , every fourth segment is an axillary without a syzygium ; but Bohlsche 2 has found 

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

 but the last two are united 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 

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

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

 seems to have decided upon calling it Actinometra. Midler named it simply Comatula. 



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

 determined by myself or by others 3 , as far as I know, to belong to the type Actiuometra. 

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

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



Ant. adeonte. Ant. macrocnema. Ant. phalangium. 



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. Sarignii. 



To these must be added 



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



Ant. bicolor, Mus. Paris. Ant. dividua, Mus. Paris. Ant. polyactinis, 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 

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

 the character of the oral pinnules. 



C. Cumingii. C. elongata. C. flagetlata. 



C.japonica. C. nova Guinea?. C. tessellata, 



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



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

 (§ 21) In Act. yolymorpha, as in all Actiuometrce, the mouth (PI. I. figs. 6-16, m) 



1 ' Gattuug Comatula' p. 28. 



: '• Uebar Actinometra Bennettii und erne neue Comatida-Aib {Antedon Dubenii) " Wiegm. Archiv, l^GG, i. p. 90. 



3 Dr. Liitken has named several new species of Actinometra besides Aet. robusta — for example, Act. tenant; and 

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

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

 fication given in the previous section. 



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

 scriptions (Jahresber. d. Schlesisch. (Jesellsch. 1375, Nat.-Hist. Sect. pp. 54, 55) are, unfortunately for me, not to be 

 obtained in this country. 



