52 



PORIFERA. I. 



ill the place quoted, also says that the genus is most closely allied to Reniera, but later he seems 

 to have changed his opinion, in so far as he in 1894 (Une reforme dans la classific. des Halichondrina, 

 Mem. de la Soc. Zool. de Fr. VII, 9) places it in the subfamily GelliodincF. I must suppose, however, 

 that Cladocroce fibrosa is closely allied to the lamelliform i?f«/(?w-species treated of here, and I think 

 it doubtful whether this genus can be kept apart from Reniera. Cladocroce fibrosa has spicules of a 

 length of 0-6"'", which is a considerably greater length than is reached by the spicules of the species 

 described here, but in this respect it is well to notice that in the R. sp. b. mentioned before, the spi- 

 cules reach a length of o'327""". 



Metschnikowia Grimm. 



The form varying, as f/i inner or thicker criists, or erect, more or hss regularly cyliiidric or 

 irregularly lobate. The skeleton forms a similar network as that in Roiiera. The ends of the spicules 

 are united by a most frequently very slight mass of spongin. Spicula are oxea or strongyla, everywhere 

 or for the greater part set witli small spines. 



I. M. spinispiculum Cart. 

 PI. XII, Fig. 4 a— b. 

 1876. Isodictya spinispiculum Carter, Descript. and Figures of Deep-Sea Sponges etc. on board 

 «Porcupine», Ann. Mag. of Nat. Hist. Ser. IV, Vol. XVIII, 310, PI. XV, fig. 42. 



The form irregularly roundish or lobate, sometimes erect and irregularly cylindric. The surface 

 with small, projecting pro7tnnences, caused by the skeleton. The skeleton consists of a chiefly unispictdar 

 network of triangular or tetrahedral meshes. Spicula spined strongyla ivith curved ends, the length 

 o-2o8— 0-238""". 



Of this species there are in the collection five .specimens, none of which are attached, but they 

 appear all to have been broken off. With regard to the three specimens the form is erect and more 

 or less irregularly cylindric; one shows a beginning division into two branches; the fourth specimen 

 forms a little oblong cushion, and the fifth is irregularly lobate. The largest of the erect specimens 

 has a height of 22'"'", and the irregular lobate specimen has a greatest extent of 23'""'. The consistency 

 is rather firm. The surface shows, especially under a magnifying glass, small prominences, but is not 

 shaggy or provided with projecting spicules. The colour (in spirit) is whitish yellow. The dermal 

 membrane is thin and transparent, and no particular dermal skeleton is found, but the membrane is 

 resting on the skeleton below ; the nodes of this skeleton projecting a little, small prominences are formed. 

 The small, round subdermal cavities .shine through the skin. The pores are round, and have been 

 measured of sizes from 0-098 — 0-119™"'; the greater part is situated in the meshes made by the skeleton 

 below. With regard to oscula., round openings, to be sure, are found here and there; but these open- 

 ings, at all events the greater part of them, are scarcely anything else than subdermal cavities, over 

 which the skin has been torn off; on the other hand, openings of a diameter of ca. i"™ are found in 

 a few of the specimens, leading into a cavity which continues some way just below the skin and 

 only covered by it; from this cavity canals go down into the sponge. 



