XI 8 PORIFERA. II. 



and with the peculiar palmate chelae that were characteristic of Homceodictya in the sense of Ridley 

 and Dendy. Thus the genus is divided in three groups, which groups, however, can scarcely be 

 of generic importance, as arcuate and palmate chela; may occur in the same species (for inst. Espcri- 

 opsis forcipula Ldbk.), and the peculiarity of the Honioodictya-c\\e\a. is also found elsewhere, for instance 

 in several Espcriopsis-species (see p. 15). 



At present it is not possible to decide, which of the described species are to be referred to 

 Desmacidon, and which to Homosodictya. The case is that when no figures are given, it cannot be 

 seen from the commonly used expression ctridentate isochelae whether the question is of arcuate chelat- 

 or ancorse; and even if figures are given, they must be good ones to give sure information. I shall 

 here therefore only enumerate some species, which with certainty belong to Homa-odictya : 



Microsclera. 



H. palmata Johnst Homceodictya-chelae. 



1885. - (Myxilla) flabclliformis Arm. Hans Chelae arcuatae. 



1887. - (Desmacidon) conulosa R. and D Chela; palmatae. 



1887. - ( — ) ra/uosa R. and D Chelae arcuatae. 



1887. - kerguelenensis R. and D Homceodictya-chelse. 



1887. - grandis R. and D Homceodictya-chelae. 



1889. - (Fibularia) raphidifera Tops Chelae arcuatae, rhaphides. 



1903. - (Desmacidon) setifera Tops Cheke palmatee. 



1904. - ( ) peltata Tops Chelae arcuata;, rhaphides. 



None of these species have sigmata, and it may be doubtful, whether such are found in 

 the genus. 



1. H. flabelliformis Arm. Hans. 

 PI. IV, Figs. 2— 3. PI. XIII, Fig. 5 a— e. 



1885. Myxilla flabelliformis Armauer Hansen, The Norwegian North-Atlantic Exp. XIII, Spongiadae, 



12, PI. II, fig. 14, PI. VI, fig. 6. 

 1903. Desmacidon clavellata Arnesen, Bergens Mus. Aarsberet. 1903, Nr. 1, 13, Taf. II, Fig. 2, Taf. IV, 



Fig. 4. 



Erect, stalked, broadly leaf-shaped (grown specimens) or chib-shaped (young specimens). Tin- 

 dermal membrane a thin film with scattered spicules. The skeleton consists of polyspicular primary 

 fibres passing from the stalk into the leaf and bending in a sheaf-like way to all sides towards the sur- 

 face; they are connected by transverse spicules most frequently placed singly. Spicula: Megasclera oxea 

 of two sizes, large ones in the skeleton. 0-41— 0-55""", smaller ones in the skin. 0-268— o-jj"""; micro- 

 sclera chela arcuata-. highly curved, o-ojo — 0-04""". 



Of this species we have two larger, somewhat damaged specimens, and two small ones. The 

 species has below a stalk attached by a somewhat expanded basal part, but the specimens in hand 

 are torn off, with the exception of the smallest one, which is attached to a stone. Arnesen 1. c. 



