ATLANT. DEEP-SEA EXPED. 1910. VOL. IV.] 



SPONQIA. 



19 



Date 



Locality 



Depth 

 m. 



Temperature 



Name of expedition 



Literature 



1885 



Lat. 31,63° 10' N. long, 5° 00' E. 

 (St. 31) 



S63 



1131 . 



2317 



2394 



1535 

 1043 



-^ 0,15° C. 



-r- 1,1° C. 



-=- 1° C. 



Ncrw. North-Atlant 

 Exp. 



„M:ch. S.:rs" 

 Ingolf-Exp. 



„Princesse Alice" 

 ..Michael Sars" 



Vide — Lundbeck: Porifera 

 Desmacidonidae (pars) in Da- 



1902 



Lat. 6,0° 19' N. long, 5 1 39' W. 

 (Faroe-Channel) 



nish Ingolf-Exp., vol. VI. 2. 

 1905, p. 86. 



Ibidem p. 87. 



1905 



Lat. 69° 57' N. long, Q>° 44' W. 

 (St. 112) 



Ibidem p. 83. 





Lat. 69° 31' N. long, 7° 06' W. 

 (Norwegian Sea betwce.i J.m 

 Mayen and Iceland 





1909 

 1910 



Lat. 76° 56' N. long, 9° E. 

 (Spitzbergen (Horn Sound) . . . 



60° 51 ' N., 40° 38' W, 



Topsent: Etudes sur qlq. cla- 

 dorhiza. Bull. Institut oceono- 

 graphic Monaco, No. 151. Sept. 

 1909, p. 6. 



Myxilla O. Schmidt. — (Dendoryx Gray 1867). 



Myxllla established by Oscar Schmidt in 1862 is 

 a genus wich has been much discussed, and its diagnosis 

 has often been changed. Thus while Ridley and Dendy 

 make no distinction between the forms with or without 

 accessory spicules, Topsent (34) refers the former to 

 Myxilla and the latter to Dendoryx, after having revived 

 (in 1888) Gray's Dendoryx of 1867. Thiele however 

 (33, p. 953) states, that Topsent' s diagnosis of Dendoryx 

 must be applied to Myxilla. And finally Lundbeck 

 follows Thiele and includes in Myxilla (type M. rosacea 

 Lundbeck) thus diagnosed all forms with isancorae. In 

 this sense also Topsent now recognizes the genus (type 

 M. Incrustans), as I know by letter enclosing the draft of 

 his paper: "Sur les Eponges de la Scotia" in which 

 he deals with the question. He recognizes the genus 

 Myxilla with the above diagnosis and maintains Dendoryx 

 in the following sense: "Dendoryx, novo sensu, type D. 

 irrigularis (Bow.) Gray, a squelette reticule et herisse aux 

 noeuds, avec isocheles." 



Thus, the following species, with which I have identi- 

 fied several specimens from station 53, cannot be called 

 Dendoryx pectinata, but ought to be called Myxilla 

 peetinata — were it not for the peculiar form of the 

 isancorae, which has caused Lundbeck (17, p. 153) to 

 suggest, that it may perhaps be an Iotrochata without 

 birotula. It is difficult to decide this question in the 

 present state of our knowledge, and I therefore consider 

 it most convenient, pending further investigations, to place 

 it under the genus Myxilla: 



Myxilla pectinata (Topsent) n. var. 

 (Dendoryx pectinata Topsent olim). 



PI. II fig. 2. 

 Vide litter: 34, p. 100. 41, p. 172. 



St. 53. Several specimens. 



From this station there are several nut-shaped sponges, 

 about 2—3 cm. in diameter, covering usually the whole 

 inside of musselshells. They have a rather soft consi- 

 stency — very like small lumps of mud. In spirit the 

 colour is yellowish-grey; but to judge from some spots 

 of the skin still left on the rubbed surface, it was most 

 probably in the living state darker in colour. 



Spiculation. Megasclera. The styliloxmmg the 

 reticulation of the main skeleton are curved, robust, 1.036 

 mm. long and 0.026—0.037 mm. thick (near the base), 

 and smooth (occasionally isolated spines are faintly to 

 be observed). The tylota forming the dermal skeleton 

 have well marked heads, and are 0.740 mm. long by 0.015 

 mm. thick. Microslera : The isancorae have a doubly 

 curved shaft with the characteristic spoon-like ends, the 

 margin of which is set with pointed teeth, forming a half- 

 circlet shaped comb. I have not been able to count 10 

 teeth, as in the typical pectinata, but only 7 or 8. 

 They appear as two distinct kinds without transitional 

 forms. The larger ones, few in number, are 0.081 — 

 0.111 mm. long by 0.0074 mm. thick, the smaller ones 

 0.030—0.037 mm. long. In the larger ancorae narrow but 

 rather long alae are to be observed, much like those in 

 Myxilla diversiancorata Lundb. (fig. 27 pi. XV), but not 

 seen in Topsent's figure (pi. X, fig. 6 c, 34). 



Remark: Wether Dendoryx pectinata Tops, olim, 

 as above mentioned, turns out to be a Myxilla, or, as 



