PORIFERA. II. 6 1 



of this chela were found abundantly on all stages from so fine ones, that they are hardly to be seen. 

 Levinsen I.e. has already given an account of the development of this spicule. — The construction 

 of the lower end of this chela has never been correctly understood, and neither Carter's nor Fri- 

 stedt's figures are correct. Levin sen, on the other hand, has given good figures, I.e.; the lower 

 end on PI. XXXI, fig. 7, cannot, however, appear as it is figured, when the chela is seen in the stated 

 position, but only, if it is seen considerably more obliquely from one end or the other. Neither has 

 Levin sen clearly understood that the question is of the common parts, alse and tooth, in a somewhat 

 modified shape. 2. Forcipes. These are of the common form with a round bend above; the legs 

 are parallel or more or less diverging, and end in a small swelling; the upper part between the legs 

 is somewhat thickened, and appears, especially when the forceps is seen from the side, as a tubercle- 

 like swelling. The length is 0-038 — o - 048 mm , and the thickness above is ca. o-oo2i mm ; the thickness of 

 the middle of the legs does not exceed o-ooi4 mm . The chelse occur in enormous numbers; they are 

 partly found in the tissue, but especially in the dermal membrane, in which they are exceedingly close 

 packed, so as to render it quite shaggy ; they appear always to be turned with the larger end outward. 

 In contradistinction to the chelse the forcipes are limited in their occurrence, being only found in the 

 point of the sponge, as has been pointed out by Levin sen; in this respect it is an interesting fact 

 that in the mentioned leaf-shaped specimen the forcipes are found throughout the leaf-shaped part, 

 which fact would seem to prove this whole part to correspond to the point of an individual of the 

 common form. 



Embryos. In several individuals of this sponge embryos were found. They are situated in the 

 tissue in very great numbers; they are globular, the larger ones a little oval, and they are rather 

 small; the size is very varying, and was measured from 0-05— o-27 mm . They are in the tissue surrounded 

 by a membrane, and they appear each of them to be situated in a little cavity. Their spiculation 

 presents some points of interest. They are provided with both megascleres and microscleres. The 

 megascleres are straight or often rather strongly curved tylostyli and subtylostyli, most frequently with 

 rounded end; they are often more or less irregularly formed, and besides quite irregular forms occur, 

 small short styli, strongyla, and other forms, as also small, more or less irregular siliceous globules. The 

 greatest length measured of the needles was o-i2 mm , and they may reach a thickness of ca. o-oo7 mm , but 

 they occur in all degrees of thinness, down to exceedingly thin ones; in the same embryo, however, they 

 are always of about the same thickness. They are only found in small numbers, 12—16 needles were counted 

 in each embryo. They are always arranged in a particular way in the embryo, viz. as a bundle placed 

 radiately with one end towards the centre and the other towards the periphery; this bundle may per- 

 haps be interpreted as the first indication of the axis. The needles of the bundle are turned in differ- 

 ent ways, some of them have the head-end turned inward, others outward. The microsclera are 

 anisochelae occurring in no small numbers, as well fully developed ones as developmental forms, but 

 they are considerably smaller than the chelae of the grown individuals, their length being only o-oi4 mm . 

 In the smallest embryos no spicules were seen. 



Observations on the synonymy. In spite of the peculiar and evidently very diagrammatic figure 

 of the exterior found in Carter, it may no doubt be regarded as certain that the question is of his 

 species. If, for instance, his figure is compared with my figure of the exterior PI. II, fig. 14 it will be 



