INVERTEBRATA, CRYPTOGAMIA, MICROSCOPY, ETC. 741 



Sections through one of these plated Hyponome-diska show that all 

 the various structures which underlie the grooves of ordinary Comatulcp 

 are present and exhibit their usual characters. 



The examination of the ' Challenger ' Comatulce has entirely con- 

 firmed the opinions held by Dr. Liitken and the author respecting the 

 distinguishing characters of Antedon and Actinometra. Both agree in 

 referring forms with a (sub) central mouth, five equal ambulacra, and 

 no terminal comb on the oral pinnules, to Antedon. On the other 

 hand, species with an eccentric mouth, a variable number of unequal 

 ambulacra, and a terminal comb to the oral pinnules, belong to 

 Actinometra. 



It will be seen at once that these characters are of no use in dis- 

 tinguishing the genera of fossil Comatulce. But there are very con- 

 siderable difierences in the shape of the radials and centrodorsal piece 

 in Antedon and Actinometra respectively, and as these are exactly the 

 parts which are most met with as fossils, the generic determination of 

 a fossil form is almost as easy as that of a recent one, which has given 

 up its disk to produce a Hyponome. The author has shown elsewhere 

 that in Act. polymorpha and Act. Solaris, half, or even more than half, 

 of the arms may have neither ventral groove, tentacles, ambulacral 

 epithelium, nor ambulacral nerve. No less than twenty-three out of 

 the forty-eight species of ' Challenger ' Actinometrce may have more or 

 fewer of such ungrooved arms, in which the ambulacral nerve is 

 entirely absent. These arms are usually those which come off" from 

 the hinder part of the disk, but in one gigantic Philippine species with 

 over 100 arms there are several ungrooved arms upon each radius. 

 Evidence of this negative character appears to the author to be a 

 serious objection to the German view, that the ventral bands con- 

 stitute the sole nervous apparatus of the Crinoids ; and on the other 

 hand, to strengthen the opinions held by Dr. Carpenter and by the 

 aiithor, that the axial cords of the skeleton are also nervous in 

 character. 



Coelenterata. 



New Genera and Species of Corals.* — The Eev. J. E. Tenison- 

 Woods describes three new genera and one new species of Madrepo- 

 raria corals; the genera being Vasillum (tuberculatuni), Diechorcea 

 (boletiformis), and Phyllopora (^spinosa) and the new species Balano- 

 phyllia dentata. 



In Vasillum (one of the Turbinolidfe) the corallum generally 

 represents Splienotrochus, but in place of a columella the septa of 

 opposite sides of the calice unite to form separate comjiartments. 



DiecJiorcea (one of the Poritidfe) is a very remarkable instance of 

 the appearance in the present epoch of characters which belong to 

 long-extinct forms of life united to others which are our commonest 

 forms of zoophytic life. Microsolena is a fossil coral of the upper Jura 

 of France and great oolite of England, and is distinguished by having 

 all the individuals enclosed in a strong or compact ei^itheca, and the 

 septal apparatus confluent. The zoothome thus resulting is massive, 



♦ 'Proc. Linn. Soc. N.S.W.,' iii. (1878) p. 92. 



