466 RECOBD OF CURRENT RESEARCHES RELATING TO 



are being produced^ wliicli form a root-tuft to the bud. Wlien the 

 bud leaves the parent it consists of a unilaminar external layer of 

 distinct cells — to which, however, it is undesirable to apply the name 

 of ectoderm — but mainly of closely-packed mesoderm cells without 

 membranes or intermediate substance ; a small number of ciliated 

 chambers are present. Further development could not be satisfac- 

 torily traced. No ova were found in females between June and 

 August, so there is perhaps an alternation of sexual and asexual repro- 

 duction. 



Of Tetliya, a new species is described from the rocks between tide- 

 marks, T. maza. It is orange-coloured, has a single osculum, a set of 

 large stellate spicules in the dermis, and of smaller ones occurring 

 with these and also in the parenchyma ; there are two sizes of radiating 

 linear spicules, which are said to be either double- or single-pointed 

 or doubly blunt. Gemmation appears to occur only in winter ; 

 300 to 400 buds may be produced without cessation. The stellate or 

 fusiform cells surrounding the spicule bundles at the surface become 

 small, with large nuclei, and multiply ; into the masses thus formed, 

 ciliated chambers from the parent penetrate in bundles, losing their 

 connection with the maternal canal system. The exterior part of the bud 

 now consists of mesoderm cells, while the centre is occupied by 

 radially arranged masses of ciliated chambers and their canals ; it is 

 extruded by a bundle of spicules from the parent. The subcortical 

 spaces are formed in the mesoderm by separation of its cells, and be- 

 come clothed with endothelium ; the mesoderm cells mostly become 

 stellate or fusiform. Spicules also appear before the bud is set fi'ee, 

 but no osculum or subdermal cavities. 



Asexual Reproduction of Leucosolenia* — The species on which 

 M. Vasseur's investigations were made was L. botryoides (the Ascandra 

 variabilis of Haeckel) ; the interest of the paper lies in the fact that, 

 hitherto, no mode of asexual reproduction has been observed in the 

 Calcareous Sponges, although it is well kno\vn in the Fibrospongise. 

 Professor Haeckel goes so far as to say that though he has examined 

 thousands of CalcispongiaB, he has never been able to discover the 

 formation of any gemmules. While at Eoscoff, M. Vasseur obtained 

 from the " He de Bas " specimens of this sponge, which were provided 

 with singular pyriform prolongations, in which were a number of very 

 long acicular spicules. What was, however, at first most remarkable 

 was the direction which these spicules took ; for these, instead of being 

 directed towards the termination of the tube, were turned in the oppo- 

 site direction ; the pyriform prolongations were soon observed to be 

 closed at their free extremity. 



These prolongations, or buds, as they may henceforward be called, 

 were by their interior in communication with the cavity of the sponge. 

 After this preliminary examination, some days passed before the 

 sponges were again examined. Now a remarkable arrangement was 

 seen : new prolongations had been formed, while a number had sepa- 

 rated from the parent-sponge, and others were on the point of detach- 



* ' Arcli. Zool. cxpe'r. et gen.' (Lacaze-Dutliiers), viii. (1880) p. 59. 



