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this ectoderm contains numerous deeply staining lens-shaped cells, while just below the surface 
numerous darkly granulated cells are found, connected by stalks with the base of the ectoderm. — 
Only in one single case Brook saw rests of symbiotic Algae but he could not make sure of their 
occurrence. — The mesenterial filaments are of actinopharyngeal ectodermal structure; they never 
have lateral lobes; they are often branched, but only the ends of the branchings are ectodermal. 
After this extensive research of Brook there has not been published much on this 
subject. Van Beneden (7) examined some (unnamed) forms and in the main he found the same 
facts as his predecessors. In the actinopharynx he always found a sulcus at one of the sagittal 
extremities, which sulcus is continued by a hyposulcus at the basal end of the actinopharynx, 
but van Beneden does not tell whether this sulcus is differentiated in microscopical anatomy, 
which, according to Brook, is not the case. This sulcus is found between the anterior directive 
mesenteries. Van Beneden corroborates Brook’s remark that the secondary mesenteries descend 
deeper on the actinopharyngeal side than on the side of the body wall. 
The Valdivia-material described by Schultze (11) contained i. a. a specimen of Stichopathes 
gracilis Gray, which was fit for microscopical examination but Schultze only gives a figure 
(a section through the sagittal axis) but no description. Only the situation of the mesenteries is 
described, but without a particular feature. From the figure (Schultze’s Taf. XIII, fig. 2) may 
be deduced that the mesogloea contains fibrillar connections between ectoderm and entoderm. 
Schultze remarks in his introduction: “die Konservierung mit Formol und mit Alkohol hat 
brauchbare Ubersichtsbilder gegeben; was auf diesem Wege zu ermitteln war, hat Brook an 
den Antipatharien der Challenger-Expedition beschrieben; ein tieferes Eindringen in histologische 
Feinheiten erfordert jetzt Macerationspraparate, und die miiszte sich der Spezialist selbst, von 
lebendem Material ausgehend, herstellen”. 
Finally L. Roule (14) examined three species viz. Antipathes aenea v. Koch (= Euanti- 
pathes dichotoma), Leiopathes glaberrima Esp. (= Euantipathes glaberrima) and Stichopathes 
Richardi Roule, (= Stichopathes Jiliformis (Gray) Br.) but through the bad state of preservation 
the results were not very important. Roule corroborates Brook’s data, especially as to the 
absence of an actinopharyngeal sulcus, and the continuation of the secondary mesenteries to a 
lower level on the side of the actinopharynx. He doubts the presence of nematocysts in the 
ectoderm. Stichopathes Richardi R. was in such a state that only the mesogloea remained, 
which according to Roule, is the principal part; but the loss of the ectoderm and the entoderm 
is the more inconvenient, since Roule concludes from his research that neither Antipathes , 
nor Leiopathes , nor Stichopathes have a muscle system (!) Too much value is given to this by 
Silberfeld (21, p. 26), since the very scanty material and its condition did not permit of such a 
generalisation. — Roule finds a very variable thickness of the mesogloea and explains this by 
the supposition that the genera with an unbranched colony ( Stichopathes ) or without spines 
(. Leiopathes ) compensate this loss of support by an exceedingly thick mesogloea. 
Here and there in his systematic descriptions Silberfeld (21) gives anatomical details 
also. With his specimen of Stichopathes Jiliformis (Gray) Brook (= Stichopathes variabilis') he 
remarks that the very thin mesogloea is incompatible with Roule’s opinion on this point for 
the unbranched genera; with Stichopathes japonica Silb. (— Euantipathes l0ngibrachiata) he finds 
