PORIFER.\. I. 



17 



I. H, panicea Pall. 

 PL IX, Fig. I. 



1842. Halichondria panicea Johnston, Brit. Sjiong. 114, PI. X, PI. XI, fig. 5. 



1866. — — Bowerbank, Mon. Brit. Spongiadse, II, 229, III. PI. XXXIX and XL. 



1870. Pellina bibula O. Schmidt, Spongienf. atlant. Gebiet. 42. 



1870. Amorphina panicea O. Schmidt, 1. c. 77. 



1881. Amorphina megalorrhaphis Carter, Ann. Mag. Nat. Hist. Ser. 5, Vol. VII, 368. 



1887. Halichondria bibula h&^insen^ Dijmphna Togtets zool.-boL Udbytte, 352, 11, Tab. XXX, fig. 4 a— b. 



1887. Halichondria panicea Ridley and Dandy, Challeng. Report, Monaxonida, Vol. XX, 2, PI. II, figs. 2, 3. 



1887. Amorphina panicea Fristedt, Vega Exp. Vetensk. lakttag. IV, 421. 



1887. Amorphina grisea Fristedt, 1. c. 425, PI. 24, fig. 10, PI. 27, fig. 10. 



Of this common species we have a large number of specimens. Itjis most frequently incrusting, 

 especially on algae, and from this form it grows out into large cushions or lumps, and consequently it 

 is formed as flat cakes, cushions, or roundish or lengthy lumps. Only one specimen, from Reykjavik, 

 has a more definite form, conical, tapering tubes, or cylindrical, at the summit flat tubes rising from 

 a flat spreading; the tubes have at the summit an osculum leading into an oscular canal. This form 

 corresponds with the picture of Bowerbank, PI. XXXIX, fig. 5 and PI. XL, fig. i. In the lumpy 

 forms the oscula are spread and most frequently only present in small numbers. In almost all the 

 specimens the dermal spicules form the well-known regular net of meshes with three, four, or many 

 sides, in which net the pores are lyiug, often so close that the membrane is reduced to a mere net- 

 work. Now this net may be rather varying in appearance, and may also be quite wanting, so that 

 the dermal spicules are h'ing closely packed and in all directions. The character on which the species 

 must chiefly be based, is the form of the spicules; they are ver)- long tapering, always a little cur\ed, 

 and this curve is exceedingly frequently seen as a rather sharp bend in the middle. The size of the 

 spicules is somewhat varying from 0-35—1"™; this latter size is given by Carter for his species H. 

 megalorrhaphis^ his own opinion of which is that it is only a variety of panicea^ and Ridley and 

 D e n d V give, 1. c, several sizes between the measures given above. The largest length of spicules 

 measured by me, is ca. o-6""". Among the spicules are also seen styli and monstrous forms, but always 

 only sparingly. The genus Pellina of Schmidt, which was based on the presence of a distinct skin 

 with a net of spicules, is, as has been shown by Grentzenberg (Die Spongienfauna d. Ostsee. Inaug. 

 Dissert. Kiel, 1891, 12) and Levinsen (Det vidensk. Udbytte afKanonbaaden «Hauch»sTogter, 1893, 415) 

 by an examination of the original specimens of Schmidt, not to be distinguished from the genus 

 Halichondria^ and the species Pellina bibitla is identical with H. panicea. I have had occasion to 

 examine one of the specimens of Fristedt of Amorphina grisea, and have not been able to find any 

 character separating this species from //. panicea. 



As has already been mentioned, some of Bower banks species will, no doubt, prove to be 

 identical with H. panicea, what can only be decided with certainty by an examination of original 

 specimens. Levinsen, in the work quoted above, has referred Spongia coalita Mxiller (Zoologia 

 Danica, III, 71, Tab. CXX) to panicea, and judging by the figure it can scarcely belong to any other 

 .species. Also Johnston's H. coalita (Brit. Spong. and Lithophytes 135, PI. XII, fig. i) has by Le- 

 vinsen been referred to this species; the spicules pictured by Johnston, do not, to be sure, resemble 



The IngoI!-Exp-'lition. VI. i. _ 3 



