PORIFERA. I. 



37 



Of the smaller fragments one is a specimen, the lower part of which is wanting; it is mnch 

 smaller than the specimens mentioned above, the length being 21'"'", the breath i^m™; the osculum is 

 4™™. Further may be noted that the spicules of this fragment are a little smaller than those of the 

 larger specimens, their length being on an average 019™™, and their thickness o-oi2""". 



The determination of this species as R. urceolns may no doubt be regarded as certain; to be 

 sure, the description cited is very short, but as well the description as the picture agrees very well 

 with the present species; the description cited is by Rathke, and the plate b)' Vahl, and consequently 

 O. F. Muller cannot be cited as the author of the species. Johnston (British Sponges and Lithophytes, 

 1842, 175) supposes Spongia urceohis to be a variety of Gran fin comprrssa\ but alread)- the size and 

 also the form show that such cannot be the case. 



Chalin-ida robustior which, with a query, I have referred to this species, was established by 

 Schmidt I.e. on two small fragments from Iceland, found in our museum. The examination of these 

 fragments has shown that their spicules agree completely with those of the present species, and I 

 think it rather sure that they are stalk-pieces of R. itrcfohis. The polyspicular longitudinal fibres that 

 are rather well developed in the stalk, have been the cause why Schmidt has thought to have to 

 do with a Chalinine. 



Locality: Iceland, two whole specimens (Steincke); Eastern Iceland, depth 38 fathoms, a little 

 specimen (Horring); the northern coast of Iceland, depth 52 fathoms, a fragment (Wandel); the Faroe 

 Islands, 6 miles to the northwest of Kalso, depth 60 fathoms, one specimen (Th. Mortensen). 



From Jacobshavn in Greenland (assistant Olsen) we have three specimens, which I take to 

 belong to this species. They grow on the roots of a Laminaria; with regard to the form and size of 

 the spicules and the structure of the .skeleton, they quite agree with R. nrceolus, but the two specimens 

 have no definite form, and are incrusting; they are rather small, their greatest length being ca. 20™"'; 

 the third specimen, on the contrary, forms a pyriform tube like the form of urceolus\ this specimen 

 has a height of 20™"'. Whether these specimens be really R. urceolus, I cannot decide with certainty; 

 but if so, the small incrusting specimens are presumably quite young, and the species cannot be sup- 

 posed to rise to a tubulous form, until it becomes older; in reality the three specimens in hand form 

 a characteristic series: the first specimen is absoluteh- incrusting, and has a greatest height of 6™"', 

 the second rises from an incrusting plate to a semiglobular cushion, and has a height of io™"\ neither 

 of these specimens show any osculum; the third specimen rises to a short-stalked tube of a height 

 of 20""" with an osculum on the summit. 



Geogr. distr. In the place quoted from Zoologia danica, the species is mentioned from northern 

 Norway. 



2. R. parenchyma n. sp. 

 PI. VII, Fig. I, PI. XI, Fig.s. 2—4. 



Erect, leaf shaped, oblong-oval. The dermal metnbraue thin, without spicules; the ends of the 

 fibres projecting, and the surface consequently finely shaggy. Oscula small, only occurring on one side? 

 The skeleton a regular network of primary and secondary fibres, the fibres unispicular. Particular poly- 

 spicular fibres arefoiind rurwing longitudinally through the sponge from the base. Spicula slightly curved, 

 sharply pointed oxea, ca. o-2j8""". 



