PORIFERA. II. 



209 



structure as the chelse of the grown sponge, but reach at most a length of 0"025 mm . The specimens 

 in question were obtained in the beginning of June. 



Locality: Station 57, 63 37' Lat. N., 13 02' Long. W., depth 350 fathoms ; station 73, 62° 58' Lat. N., 

 23 28' Long. W., depth 486 fathoms. Both stations are situated south of Iceland. 



F. groenlandica Frstdt. 

 PI. XX, Fig. 3 a— e. 



1887. Forcepia groenlandica Fristedt, Vega Exp. vetensk. Iakttag. IV, 452, PI. 25, figs. 40 — 46. 

 1904. ? Trachyforcepia groenlandica Topsent, Resultats des camp, scient. du Prince de Monaco Fasc. XXV, 

 181, PI. XV, fig. 14. 

 Thickly incrusting or massive. Spicula: Megasclera: the skeletal spicules acanthostyli 0-42 — 

 °'55"""> M' c dermal spicules tylota 0-40— 0-4 47"'"'; niicrosclera of three forms, isochela; arcuatce 0-023— 

 O'ojj""", forcipes o-ojj — 0-0529""", sigmata, more or less contort, 0-114 — 0-15""". 



This species has not been obtained by the Ingolf-Expedition , and I have only before me a 

 small fragment of the type specimen; therefore I only mention the spicules more particularly, a. Mega- 

 sclera. 1. The skeletal spicules are acanthostyli; they are slightly curved, either evenly through 

 their whole length, or with the curve nearer to the upper end. The point is rather short, at most 

 middle long. The spinulation is rather scattered, but in this feature some variation may be found; 

 the spines continue out on the very point; at the head-end they are generally more closely gathered. 

 The length of the acanthostyli is 0-42 — o-55 mm , and the thickness o-on— o-oi4 ram . 2. The dermal 

 spicules are slender, straight tylota with slightly swollen ends; their length is 0-40 — o - 447 mm , the 

 thickness is ca. o-oo7 ram . b. Microsclera ; these are of three forms, isochelse arcuatse, forcipes, and sig- 

 mata. 1. Chelse arcuatse are of a similar form as in the preceding species, F. Thielei; their length 

 is 0-025— o-035 mm by a thickness of the shaft of 0-0028 — o-oo4 mm . 2. Forcipes are of a form reminding 

 much of the forcipes in F. Thielei; the shorter leg, however, is generally straight, and the longer leg 

 forms a more curved bow; they are finely spined but not so densely as in F. Thielei, and the legs 

 end in a little button. Their length to the end of the longer leg is 0-035 — o-0529 mm , and the thickness 

 in the curve is ca. 0-0014 — o-oo2i mm . 3. Sigmata are of the common form, and are more or less con- 

 tort; their length is 0-114 — o-i5 mm , and the thickness ca. 0-005 — o - oo7 mm . 



Locality: The species was taken by the Sophie-Expedition 1883, at East-Greenland, depth 125 

 fathoms. Topsent mentions it from the sea at the Azores at a depth of 1196 fathoms. 



Note. This species seems to be closely allied to F. Thielei; like this it has only one form of 

 forcipes, and the forcipes of the two species resemble each other and are of a characteristic form. It 

 is doubtful whether the F. groenlandica mentioned by Topsent is identical with the present species, 

 as its styli are very slightly spined and often smooth, and both styli and tylota are somewhat larger, 

 as also its sigmata are plane. Also Topsent' s species must be closely allied to F. Thielei, especially 

 the sizes of the spicules are rather equal, but in Thielei spines are never found on the styli; accord- 

 ingly there is some possibility that Topsent's species is an independent one. Topsent establishes 



The Ingolf-Expedition. VI. 2. 27 



