GENERAL MORPHOLOGY OF TFIE GROUP. 
Ech. 5 
In the first subclass, there are three families— (1) Asleridcc, (2) 
Ileliasteridce, (3) Drisingidoi ; the last contains the three genera, Lahidi- 
aster, Brisinga, and Pedicellaster. In the second subclass, there are (4) 
Echinasieridcc^ (5) Lincldidcn, (6) Goniasteruhe, (7) Asterinidce^ (8) 
Pterasleridai, (9) Astrojyectinidcc, (10) A r chaster idea. The last family con- 
tains as its only genus Archaster^ which Viguier thinks necessary to 
separate from Astropecten, 
Sladen (23) proposes to form a family, Astrophiarklcc, for Astrophiiira 
permira^ g. & sp. nn., Madagascar, and to define it thus : — “ Brachia cum 
disco ophiurano in corpore pentagonali inclusa. Dentes absunt. Oris 
armatura simplex et imperfecta. Pori pedum ambulacralium soptis 
angustis ad perpendiculum radii directis disjunct!. Cava iiiterbrachialia 
perlata.” Unless this form bo an extraordinary example of adaptation, 
it is probable that the describer is quite justified in regarding it as 
diminishing the distance between the Asteroidea and Opliiuroidea in a 
very marked degree. 
Von Martens (10) makes his new Ophiothcla the text for some interest* 
ing remarks on the heteractinism of certain Echinodermata, and finds 
that his present observations confirm him in his previously published 
belief, that when Starfishes have more than five arms, it is in consequence 
of gemmation after division or injuiy. (See also Naturf. 1879, pp. 103 
& 104.) 
In an elaborate and comprehensive monograph, P. H. Carpenter (5) 
deals with the genus Aciinometra. After an historical survey, he proceeds 
to a consideration of the characters of the genus, and shows by the sub- 
joined scheme the relations of Antedon and Actinometray as defined by 
Llitken and himself, to Alecto and Aciinometra^ as used by J. Muller : — 
Alecto. . . Ambulacra sym-'l Mouth (Antedon . . Oral pinnules 
metrically dis- ( central. J not specially 
tributed on the r Mouth j distin- 
disc. 3 eccentric. ( guished. 
Actinometra. Ambulacra uu- 
symmctrically 
distributed on 
the disc. 
Pp. 40-51 contain a diagnosis of A. })olgmo7pha, sp. u., and its four 
varieties. 
The skeleton is then examined, and some of its parts are discussed in 
detail. It is shown that in Comatida “ the walls and floor of the cavity 
inclosing the chambered organ are formed almost entirely by what was 
once a stem-segment, while in Pentacrinus this cavity is a part of the 
central space inclosed within the radial and basal pentagons, which 
respectively form the ventral and dorsal portions of its side walls.” An 
intermediate condition may be observed in the fossil Apiocrinidm. 
Carpenter (Zool. Anz. ii. pp. 5G9-571) details the history of the dis- 
covery of the true character of the “ chambered organ of Comatula^' in 
answer to Greef’s claim (SB. Ges. Marburg, No. 4, 1879). 
Carpenter’s researches (6) on the Comatidce of the ‘ Challenger ’ 
pedition enable him to explain the riddle of Liitken’s genus Phanogenia^ 
^ Mouth (Actinometra. Oral pinnules 
eccentric. ) with a ter- 
minal comb. 
s ; 
