2QO PORIFERA. II. 



small ones, and two forms of forcipes, also large and small ones. i. The large chelse have an 

 evenly, but slightly curved shaft, the tooth is narrowly elliptical with a longish tuberculum, from 

 which a continuation may be traced about to the end of the tooth; the alse are of the same length 

 as the tooth and are somewhat tooth-like, when viewed from the side. Their length varies from 

 0-043— 0-067""", m °st frequently it is midway between these sizes; the thickness of the shaft is 0-004 — 

 o-oo7 rara . A few monstrosities with split tooth were seen. 2. The small chelae are of a similar 

 form, the only difference being that the tooth and the ake are comparatively longer, and the tooth 

 is broader; their length is 0-021 — o-o28 mm , and the thickness of the shaft is 0-0014 — o-oo2i TOm . Develop- 

 mental forms were found of both chelae at different stages, but only sparingly. Quite singly cheke 

 were seen occupying, as to size, a middle place between the two forms. 3. The large forcipes 

 are peculiar and beautiful spicules. They have a round curve above, and continue in two very long, 

 more or less parallel, legs, one of which is always a little longer than the other; the legs may be a 

 little diverging or converging, but always only to a slight degree; when converging the}- often touch 

 each other. The forcipes are most frequently a little twisted, so that the legs intercross. They are 

 spined, and the spines are all turned upwards towards the curve, and formed in such a way, that the 

 legs may more properly be called serrated. The spines are almost exclusively found on the in- and 

 outward turned sides of the legs only, that is to say, in the plane which includes both legs; they are 

 generally more close-standing on the inward side of the leg than 011 the outward side, and 011 the 

 inward side they are especially close-standing in the middle part of the leg. At the curve the spinu- 

 lation becomes more rugged, and here some spines may be found all round. The length, measured 

 from the curve to the point of the longer leg, is 0-44— o-52 mm , the thickness at the curve is 0-0058""" 

 and about the middle of the legs it is o-oo28 mm . An interesting thing it was to find the develop- 

 mental forms of this spicule, and they are not especially rare; they are of the same, or about the 

 same, length as the fully developed spicule, but they are finer, down to very fine; then they are quite 

 smooth, only the more developed stages begin to get at little rugged in the upper part. 4. The 

 small forcipes are of a peculiar form, one leg being more than three times the length of the other; 

 the short leg is straight, while the long one with an arcuate curve bends towards the side where the 

 short leg is found. The legs end in a little knob. When seen under slight magnifying powers these 

 forcipes look as if they were rugged, but when the magnifying powers are higher, they are seen to 

 be spined, and the spines are arranged in the same way as in the large forcipes. This spinulatiou 

 and the terminal knobs of the legs, especially that of the long leg, are, however, only to be seen 

 with great difficulty. Their length is 0-028 — o-036 mm ; they are exceedingly fine, the thickness at the 

 curve not being more than 0-0007""". This small spicule is easily overlooked; it is Carter's merit 

 first to have seen it, but according to his erroneous view of the growth of the spicules he called it 

 embryonic form of the large forceps; neither has he been able to see their form correctly, nor their 

 spines. The microscleres are found through the whole sponge and in the dermal membrane, where 

 the large chela seems to be most frequent. The large forcipes occur in the tissue in bundles that 

 may almost form fibres; the single forcipes in the bundles seem all to be turned one way. 



Locality: Station 78, 6o c 37' Lat. N., 27° 52' Long. W., depth 799 fathoms, a very small fragment 

 the Faroe Islands, east of Sudero, depth ca. 150 fathoms, one specimen (Th. Mortensen). 



