PORIFERA. III. 



We have a specimen of this species which I at first thought was a distinct form on account 

 of its smaller spicules, but -which on closer examination proved to be a very young specimen of 

 appendiculatum. The specimen is globular, with a single fistula, and very small, about 3""" in 

 diameter, and thus not larger than the examined embryo. It shows quite the same structure as the 

 full-grown specimens; it has a distinct dermal layer with subdermal cavities below, and also distinctly 

 shows the skeletal structure of the inner body. The specimen is interesting in showing, that such small 

 specimens may have considerably smaller spicules than the grown specimens. It is yet no doubt only 

 the very small specimens which show in this respect any difference worth mentioning, and it is certainly 

 the case, that they very soon get spicules of the size normal to the species. The examined specimen 

 has probably just left the mother-sponge. The megacleres do not reach beyond 0-41 n " n , the chelae 

 are 0-050 mm , and the sigmates are of the same sizes as in the full grown sponge. It is interesting to 

 notice, that the chelae in this specimen are intermediate in size between the chelse in the embryo and 

 those in the grown sponge. The relatively long and fine megascleres in the embryo seem here to be 

 replaced by shorter but thicker spicules. 



Locality: Station 78, 60 37' Lat. N., 27 52' Long. W., depth 799 fathoms, about 29 more or less 

 damaged specimens; station 90, 64 45' Lat. N., 29 06' Long. W., depth 568 fathoms, two specimens and 

 some loose fistulse; further at 61 15' Lat N., 9 35' Long. W., depth 478 fathoms, a very small specimen 

 (The fishery investigation steamer "Thor"). The localities are situated on the eastern slope of the 

 Reykjanses Ridge, in the Denmark Strait and West of the Faroe Islands. 



Geogr. distr.: Carter had the species from the west coast of Ireland, depths 808 and 109 fathoms. 

 (Porcupine). 



2. H. physa O. Schmidt. 

 PI. I Figs. 12-13, PI. IV, Fig. 3. 



1875. Dcsmacidon physa O. Schmidt, Jahresber. der Comm. zur wissensch. Unters. deutsch. Meere in 



Kiel fur 187273, 118, Taf. I. Fig. 8-9. 



1887. Cornulum ascidioides Fristedt, Vega Exp. wetensk. Jakttag. IV, 495, PI. 25, figs. 12, pi. 29, fig. 21. 

 1903. Histodcrma physa, Arnesen. Berg. Mus. Aarbog 1903, 16, Taf. II, Fig. 5, Taf. Ill, Fig. 9. 

 1903. , Thiele, Arch. Kir Naturgesch. Jahrg. 1903, 385, Taf. XXI, Fig. i6a b. 



1909. , Lundbeck. Meddel. orn Gronland, XXIX, 443. 



Roundish or more irregular, sometimes somewhat erect, attached -with a broad base; provided 

 witli one or a couple of conical spouts. Stir/ace smooth. The sponge surrounded by a solid, but not 

 thick, bladdery dermal layer. Oscula at the summit of the conical spouts, the pores on the side of these. 

 The dermal skeleton formed of close-lying spicules parallel to the surface. The skeleton of the inner 

 body consisting of fine fibres and bundles of spicules, running irregularly, but at the surface parallel 

 with this; without transverse fibres. Spicula: Megasclcra strongyla ivith intermediates to subtylota, 

 0-50 0-89"""; microsclera of two forms, chel(e arcuatce o~ojj 0-058""", trichodragmata o-u 0-12""". 



This species has a shape mainly as described by Schmidt. It consists (on account of con- 

 traction or destruction of the inner body) of a bladder, formed of the dermal layer. This bladder may 



