PORIFERA. I. 



69 



they are most frequently elongated; those gathered together into bands, are smaller and most fre- 

 qnenth' round. 



Locality: Station 76, 60° 50' Lat. N., 26° 50' Long. W., depth 806 fatlioms; only one damaged 

 specimen. 



Note. The two species now described, G. luridns and iiiicroloxn, as well by their spiculation 

 as the whole other structure, thus, I suppose, also by their numerous and distinct cellules spheru- 

 leuseS'-, appear to be very nearly related; but on the other hand cliaracteristic differences are found, 

 both in spiculation and other structure; thus with regard to the spiculation, the sizes of the spicules 

 and the reciprocal proportion of their sizes, as also the different structure of sigmata. In the skeletal 

 structure is especially to be noted the difference that the spiculation of the dermal layer — and of the 

 layer inside constructed in a similar manner — is far more dense in one than in the other, and also 

 the amount of spongin is different. Finally is to be noted the difference with regard to cellules sphe- 

 ruleuses and their occurrence. 



On account of the rind-like dermal la>'er and the lamellar structure of the skeleton, as also on 

 account of both species presumabh- having been provided with a fistula , these two species might 

 be referred to the genus Occaiiapia, but then this genus would have to be extended so as also to 

 comprise species with toxa; if with Uend\- we should prefer to unite it with Rhizochaliua {Phlceodic- 

 tyoii mihi), it would accordingly contain species without microsclera, species with sigmata, and species 

 with both sigmata and toxa. In the present work, however, I have only kept the genus Occanapia 

 for the species robusta (for particulars see under this species and the introduction to the genus Plila-o- 

 dictyoii). 



5. G. primitivus n. sp. 

 PI. XIII, Fig. II a— b. 



Crust-shaped, thinner or thic/.-er. The stieletou is a rather regular network ; for a great part it 

 is uuspieular, but polyspicalar fibres are found, especially running fotvards the surface. Spicula : Mega- 

 sclera curved oxea o-ij/—o-i66"""; microsclera fine toxa o-028~o-ioy""". 



We have only this species in more or less damaged specimens, and in drj- state, so that the 

 description must chiefly be restricted to the spicules. The species grows incrusting on a branched 

 Lithothamnion, one of the specimens shows a tube. The greatest extension reached by any of the 

 specimens, is ca. 14™'". The colour in the dried state is }'ellow. As far as I have been able to judge 

 from the specimens in hand, the surface is shaggy, the dermal membrane being pierced by the ends 

 of the spicules. 



The skeleton consists of a rather regular network, partly unispicular, but also polyspicular fi- 

 bres are found in it, especially running in the direction towards the surface. The .skeletal meshes are 

 more or less rectangular. Especially the fibres running towards the surface (the primary ones) are 

 distinct, while the fibres running vertically on these are less conspicuous. In the nodes of the skeleton 

 the spicules are united by a distinct and rather copious mass of spongin. 



Spicula : a. Megasclera are oxea ; they are more or less, most frequently rather strongly, and 



