BREEDING SEASONS 



369 



spicules is the same as in the adult, but the size is considerably less. The interesting 

 feature about this sponge is that the small cortical oxea, instead of being set more or less 

 at right angles to the surface, as in the adult, are arranged in a tangential layer at the 

 surface. 



BREEDING SEASONS 



In the table given below, the evidence obtained from the finding of embryos in situ, 

 based on the records of previous authors and the results of the present study, is brought 



Table showing the approximate breeding periods of Antarctic species of 

 sponges, as deduced front the finding of ova or embryos. 



Species 



Calcarea 



Acliramorp/ia nivalis, Jenkin 

 Tenthrenodes scotli, Jenkin 

 Megapogon raripilis, Jenkin 

 Leucetta leptoraplns (PolejaefF) 

 Tetraxonida 

 Oscarella lobularis (Schmidt) 

 Plakina monolopha, Schulze 

 P. trilopha, Schulze 

 Craniella leploderma (SoUas) 

 Cinachyra barbata, Sollas 

 C. antarctica (Carter) 

 Haliclona bilamellata , sp.n. 

 Petrosia fistidala, Kirkpatrick 

 P. depeUens, Topsent 

 Adocia tremulus (Topsent) 

 Hemigellius riidis (Topsent) 

 Callyspongia flabcllata, sp.n. 

 Isodictya antarctica (Kirkpatrick) 

 /. setifer (Topsent) 

 Guitarra fimbriata. Carter 

 Mycale magellanica (Ridley) 

 Amphilectus fucuriim (Johnston) 

 Asbestopluma calyx, Hentschel 

 Tedania charcoti, Topsent 

 T. massa, Ridley and Dendy 

 T. spinata (Ridley) 

 7'. nnirdochi, Topsent 

 T. tenuicapitata, Ridley 

 lophon radiatus (Topsent) 

 Myxilla australis (Topsent) 

 Lissodetidoryx imiominata. Burton 

 Anchinoe latriincidinidcs (Ridley and Dendy) 

 A. leptochela (Hentschel) 

 Kirkpatrickia variolosa (Kirkpatrick) 

 Plocamia gaussiana, Hentschel 

 Crelta crassa (Hentschel) 

 Dictyociona discreta (Thiele) 

 Eurypon miniaceum, Thiele 

 Hymedesmia irritans, Thiele 

 Dolichacantha macrodon, Hentschel 

 Hymeniacidon dubia, sp.n. 

 Plicatellopsis flabellaia, sp.n. 

 Stylocordyla borealis acuata (Kirkpatrick) 

 Polymastia isidis, Thiele 

 Sphaerotylus antarcticus, Kirkpatrick 



Euceratosa 

 Halisarca dujardini , var. magellanica, TopsenX 

 Spongia magellanica, Thiele 



Jan. 



Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec 



Where a definite record for a given month has been obtained, a black line is used: a dotted line signifies the appro,\imate 

 period, based on the stage of development reached in the embryos. 



