^ , PORIFERA. I. 



/4 



meshes; here and there polyspicular fibres are found that seem especially to rmi towards the surface. 

 In the nodes the spicules are united by an only little conspicuous mass of spongin. 



Spic7ila: a. Megasclera are oxea, evenly or a little more sharply curved, and evenly tapering; 

 sometimes they are rather long tapering. The length is somewhat varying, in the specimen in hand 

 from 0'25 — 0-32""; the thickness is ca. O'Oi — o-oii""". b. Microsclcra; these are flagellate sigmata of a 

 similar form as those of the preceding species, but somewhat varying in form (PI. XIV, fig. 2 b); in the 

 most typical form one arm is curved, and much shorter than the other; the greater axis measures 

 0-07 — o-i™™, and the smaller axis ca. 0-05 — 0-057™™; the thickness is about 0-0028™"'. Besides the flagel- 

 late sigmata, other sigmata are also found singly, of about the common form, but with the ends highly 

 recurved; they are rather large, the length being 0-05—0-08™™; as they only occur in very small num- 

 bers, and as the flagellate sigmata are much varying in form, they might be taken to be only a va- 

 rietv of the latter; against this supposition, however, their thickness appears to tell, it being somewhat 

 greater than in the typical flagellate sigmata, viz. ca. 0-004™™ (PL XIV, fig. 2c); this fact, however, does 

 not exclude the possibility of their being varieties, perhaps monstrous varieties, of the flagellate sigma, 

 of which irregular, monstrous forms are not rarely found, reaching a colossal thickness, viz. 0-007™™. 



This species is distinguished from the preceding one, besides by differences in the length of 

 oxea, chiefly by its unispicular skeleton, and by the want (or the scarcity and form) of common sigmata. 



As I have had before me a piece of the original specimen of Fristedt, I have been able with 

 certainty to decide the species, which otherwise agrees very well with his description; Fristedt gives 

 the length of oxea to be constantly 0-35™™; my measurings of his original specimen, however, give 

 the same measures as stated above for my specimen. Neither does Fristedt mention sigmata of tht 

 common form, which he is likely to have overlooked on account of their scarcity, but the}- are to be 

 found in his specimen. 



I think the referring to the present species of the G. fiagcllifcr mentioned by L a m b e 1. c. to 

 be rather certain; he also mentions that common sigmata are found in small numbers. On the other 

 hand it is more doubtful, whether the G.flagellifer mentioned by Topsent 1. c, is the present species. 

 Topsent says that the spicules are the same as those in G.flagellifer R. and D., but besides oxea he 

 only mentions and figures flagellate sigmata, and as the measures agree rather well with those of 

 the present species, and the skeleton is described in the term «lignes unispiculees», I must suppose it 

 to be identical with the present species; at all events it seems impossible that it can be G. flagclUfer 

 R. and D. 



Locality: Skagestrand Bay on the northern coast of Iceland, depth 119 fathoms, one specimen; 

 63° 15' Lat. N., 9° 35' Long. W., a little fragment (Wandel). 



Gcogr. distr. The Davis Strait, depth 70 fathoms (Fristedt); the Gulf of St. Lawrence, depths 

 37—80 fathoms (Lambe); ?Gascony Bay, depth ca. 200 fathoms ( Caudan»). 



Note. Thus it appears that at all events two distinct species with flagellate sigmata are 

 found ; these species have been intermingled, the existence of a flagellate sigma obviously having been 

 regarded as a proof of the identity of the species. The first author, who mentions and figures such a 

 sigma, is O. Schmidt (Spongienfauna des atlant. Gebiet. 1870, 53, Tab. V, Fig. 15). He mentions it 



