PORIFERA. II. 



*53 



distinctly thicker than the other, and the finer they are, the more conspicuous is this feature. Mon- 

 strous forms with several swellings are not unfrequently found. Their length varies from 0-226 — 0-32™"', 

 and the thickness from 0-005 — o - oio mm . b. Microsclera ; these are of one form, plurideutate isancoras 

 spatuliferse; they remind of the ancorse of the preceding species, but are more slender; the shaft is 

 somewhat curved, either evenly, or, what is frequently the case, with a somewhat sharper bend in the 

 middle. At either end is found a number of teeth which seems most frequently to be five, but may 

 also be six or seven, and the number may be different at each end; otherwise some irregularity is 

 found in the construction, the teeth may be of different length, often in such a way, that the lateral 

 teeth are the longest, but also often in a quite irregular way. A narrow ala is found at each end, 

 also often showing some irregularity; it continues generally as a quite narrow rim along the middle 

 of the shaft. The length of the ancorse varies from 0-071 — o - 097 mm , and the thickness of the shaft is 

 0-0042 — o-oo57 mm . The ancorae are found throughout the sponge, but are not especially seen in the 

 dermal membrane. 



Locality: The Ingolf, station 127, north of Iceland, 66 ; ' 33' Lat. N., 20 05' Long. W. , depth 44 

 fathoms; the Bay of Skagestrand in Iceland, depth ^ fathoms (Ditlevsen); Axarfjord, depth 20 fathoms 

 (H. M. S. «Beskytteren» Otterstrom). Three specimens in all. 



Note. The present species and the preceding one are closely allied to each other, and at first I 

 was inclined to regard them as one species; it is, however, chiefly the occurrence of the peculiar pluri- 

 dentate ancorse, by which they become so closely allied, while other characters, which are quite 

 constant in the material in hand, separate them from each other. These characters are especially 

 the occurrence of the two different ancorse in one species, while in the other only one form occurs, 

 the marked difference in the form of the dermal spicules, and the difference in the skeletal structure. 



Of il/y.x^rt-species with pluridentate ancorse two have hitherto been described, viz. the Stelo- 

 doryx procera Tops, with five-toothed ancorse 1 ) mentioned before under pedunculated, and the Dendoryx 

 dentata described in the same place (172, PI. XIV, fig. 19) with ancorse with five to six teeth at either 

 end; both species are Myxilla-speexes. 



Of the Dendoryx ■pectinata with peculiar ten-toothed ancorse established by Topsent in 1892, 

 on the other hand, I dare say nothing with certainty; the species might perhaps be an Iotrochota- 

 species without birotulse. 



Lissodendoryx Tops, (emend.). 



The exterior passes through all forms, from incrustations tlirough massive, often more or less 

 lobed forms, to erect, club-shaped, or finally digitate or richly branched forms. The, skeleton is somewhat 

 dependent on the form ; it may be a diffuse and quite irregular polyspicular reticulation, in the massive 

 forms longer fibres may be found, in the branched forms distinct primary longitudinal fibres may occur, 

 and it may finally be of dendritic type. Spongin is present more or less copiously. Spicula: Megasclera: 

 the skeletal spicules are smooth or spined styli. the dermal spicules are diactinal, tornota, iylota, strougyla, 



!) Perhaps two species ma}- be hidden under this one, Topsent mentioning a specimen with considerably larger 

 megascleres and with ancorse with five to six teeth. 



The Ingolt-Expedition. VI. 2. 20 



