REPORT ON THE KERATOSA. 43 



fragments of spicules and small sand-grains ; tlie capsules with cellular elements found 

 within the fibres by Selenka i^oc. cit., p. 566, pi. xxxv. figs. 3-4) were not to be seen. 



Colour. — Pale yellowish. 



Habitat.— Station 186, September 8, 1874, lat. 10° 30' S., long. 142' 18' E.; depth 

 8 fathoms ; coral mud. ,, 



Psammoclema, Marshall. 



Spongelidas with small flagellated chambers ; external surface smooth. 



Psammoclema ramosum, Marshall (PI. III. fig. 8 ; PI. IV. fig. 1). 



Psammoclema ramosum, Marshall, Zeitschr. f. wiss. Zool., Bd. xxxv. pi. vii. fig. 12, 1880. 



It is sufficient to compare the drawing of this form given by Marshall with that 

 given by me on PI. IV. fig. 1, in order to become persuaded of the fact that both the 

 Challenger and Dr. Marshall's specimens belong to the same sj)ecies. There are, however, 

 in the description which Dr. Marshall gives of his specimens, two points at variance with 

 my observations, but I am inclined to explain one of them by a mistake on the part of Dr. 

 Marshall, and the other by a real difi"erence in organisation but of no essential nature. 



It has been stated by Marshall that the skeleton of his Psammoclema ramosxim 

 is tree-like, the main fibres sending lateral branches which ramify in their turn but form no 

 anastomoses. I can state the same with respect to the xipper ends of the branches of the 

 animal, but so far as other parts of its body are concerned, I discerned the anastomoses 

 clearly (PI. III. fig. 8). Again, Dr. Marshall believes the canal system of this species 

 to be of special interest. He says : " Die Munddfi"nungen befinden sich alle auf einer 

 Seite, wie bei manchen Formen von Halichondria oculata, Grant, und bei Veluspa 

 polymorpha var. digitata, Miclucho. Es scheint dies dafiir zu sprechen, dass der Schwamm 

 nicht aufrecht wachst, sondern wie viele Pflanzen im Meere, horizontal. Ein aufrechtes 

 Wachsthum diirfte wohl auch schon bei der Schwere des Schwammes seiner geringen 

 Festigkeit und Widerstandsfahigkeit gegeniiber unmoglich sein."' Indeed, on some 

 branches of the Challenger specimen the oscula were all found on the same side, but on 

 others they were scattered everywhere, and having examined the external surface of the 

 specimen, I found all its parts equally smooth and clean. I must therefore difier from 

 Dr. Marshall with regard to his conclusion as to the kind of o-rowth of the animal. I think 

 it grows vertically, and am inclined to believe that the peculiarity in the disposition of the 

 oscula on Dr. Marshall's specimens is characteristic only of the individual. For a more 

 detailed description of the animal, I refer the reader to the paper of Dr. Marshall above 

 mentioned, and will only add that its flagellated chambers agree closely as regards form 

 and size with those of my Psammoclema vosTuaeri (PI. III. fig. 6), and that, on the 



1 Loc. cit., p. 112. 



