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52
den,1 ytrer sig i sin Afhandling: „North-American
Starfishes" 2 saaledes: „From an examination of the hard parts,
it is evident that Solaster papposus and Solaster endeca
should not be included in the same genus, having really
nothing in common, beyond the great number of arms. The
accompanying descriptions will fully show my reasons for
placing these two species in different genera." I hans
Beskrivelse over Solaster papposus og endeca kunne vi ikke
finde en saa stor Forskjellighed, at den skulde kunne
begrunde deres Adskillelse i to Slægter, og vi maa i saa
Henseende være enige med Viguier i, at det er noget
vanskeligt at forstaa, hvorfor denne Distinktion er gjort.
Professor Agassiz siger selv i sit nysnævnte Arbeide,
pag. 212: „In Solaster endeca the arrangement and
general structure of the ambulacral and inter ambulacral plates
are identical with those of Crossaster —–. The
fundamental difference between the genera, Crossaster and
Solaster, lies in the structure of the abactinal floor. The
actinal floor between the arms is composed of small,
somewhat elongated plates, arranged in more or less regularly
diverging rows, quite similar to those of Crossaster."
Ifølge det her anførte er det fornemmelig Ryggens
Hudskelet, som Agassiz lægger saa stor Vægt paa, at han
lader dette være det afgjørende for Slægtens Deling. Dr.
Viguier3 har, i sin Afhandling over Asteridernes Skelet,4
temmelig klart godtgjort, at Hudskelettet hos Solaster
papposus ikke i nogen saa væsentlig Grad afviger fra det hos
S. endeca, at nogen Deling af Slægten som Følge deraf
skulde være nødvendig. Vore Undersøgelser bringe os til
heri at være enige med Dr. Viguier; vistnok er det saa,
at hos Solaster papposus ere Maskerne i Kalknettet meget
større, end hos S. endeca; men dette kan kun komme i
Betragtning ved Artsbestemmelsen.
Hos Solaster affinis ere Maskerne mindre end hos
Sol. papposus; hos Sol. fur cif er ere de endnu mindre, og
hos den af os som ny opstillede Art, Sol. glacialis, nærme
Maskerne i Tæthed sig overordentlig meget til Sol. endeca.
Hos Alle dannes Nettet af større eller mindre, aflange eller
kantede Kalkstykker, der taglagte dække hinanden og danne
kortere eller længere Bjelker, ved hvis Forbindelse Nettet
fremkommer, Tab. IX, Fig. 5, c. 7, a. 9, l). 11, a.
Bugfladens Interbrachialrum ere hos alle de nævnte
Arter optagne af Kalkplader, der dels ere aflange, dels
1 I System der Asteriden, Müller & Troschel, er Forbes’s
Slægtsnavn Solaster atter optaget for papposus, og Crossaster er opført som
Synonym.
2 Memoirs of the Museum of Comparative Zoology at Harvard
College, Vol. 5, No. 1, pag. 98. Cambridge 1877.
3 Anatomie comparée du squélette des stellérides par le Dr.
Viguier. Archives de Zoologie experimentale et générale. Tome 7,
pag. 138. 1878.
4 1. c. pag. 112.
it.1 thus expresses himself, in his Memoir „North
American Starfishes."2 „From an examination of the hard"
„parts,l"it is’ evident that Solaster papposus and Solaster en-"
„deca should not be included in the same genus, having"
„really, nothing in common, beyond the great number of"
„arms. The accompanying descriptions will fully show"
„my reasons for placing these two species in different"
„genera." In his description of Solaster papposus and
endeca, we have been unable to find, any such difference as
would substantiate their subdivision, and in this respect,
we share the opinion of Viguier, that it is somewhat
difficult toTcomprehend the reasons for making such a
distinction.
At page 112 of the work just cited, Prof. Agassiz
himself says: „In Solaster endeca, the arrangement and"
„general structure of the ambulacral and interambulacral"
„plates, are identical with those of Crossaster —–"
„The fundamental difference between the genera Crossaster"
„and Solaster lies in the structure of the abactinal floor."
„The actinal floor between the arms is composed of small,"
„somewhat elongated plates, arranged in more or less reg-"
„ulaiiy diverging rows quite similar to those of Crossaster."
According to this citation, it is the abactinal dermal
skeleton which Agassiz lays greatest stress upon, and
adopts as the decisive feature, in arriving at the generic
subdivision. Dr. Viguier3 in his Memoir on the skeleton
of the Asteridcei has pretty clearly established, that the
dermal skeleton in Solaster papposus does not differ in
such material degree from that of Solaster endeca, that any
division of the genus should be necessary, in consequence.
Our researches lead us to agree in this respect with Dr.
Viguier. It is, indeed, the fact, that the meshes of the
reticulation are much larger in Solaster papposus than in
Solaster endeca, but this can only be accepted as material,
in diagnosis of the species.
In Solaster affinis, the meshes are smaller than in
Solaster papposus; in Solaster furcifer, they are still
smaller; and in the new species Solaster glacialis, which we
have presented; the meshes, in regard to closeness,
approach in extremely marked degree, to those of
Solaster endeca. In all of these, the reticulation is formed, of
larger or smaller, oblong, and angular, calcareous ossicles,
which laminate imbricately with each other, forming longer
or shorter rods, which unite, and produce the reticulation
(Pl. IX, fig. 5, c. 7, a. 9, b. 11, a).
The interbrachial space of the actinal surface, is
occupied in all the above named species, by calcareous
1 In the „System der Asteriden". Müller and Troschel,
Forbes’ generic designation Solaster is again adopted for papposus, and
Crossaster is stated to be synonymous with it.
2 Memoirs of the Museum of Comparative Zoology at Harvard
College Vol. 5, No. 1, pag. 98. Cambridge 1877.
3 Anatomie comparée du squelette des stellérides par le Dr.
Viguier. Archives de Zoologie expérimentale et générale, Tome 7,
pag 138. — 1878.
4 1. c. pag. 112.
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