Dr. W. Djbowski on Lubomirskia baicalensls. 33 



The colour of the sponges is for the most part more or less 

 dark grass-green ; sometimes, however, they occur olive-green 

 or brown ; only those sponges which come from considerable 

 depths (60-100 metres), or have grown under stones, are 

 almost colourless. The sponges of an indeterminate dingy 

 greyish colour are probably dying or dead stocks. 



The following parasites have hitherto been observed upon 

 the Baikal sponges — Qammarus parasiticus^ G. violaceus^ 

 and G. violaceus var. virens^. 



[P.S.— On the 29th of May last I received from Dr. Dy- 

 bowski small fragments of all the freshwater sponges from 

 Lake Baikal in Central Asia and the Pachabica-See at its 

 south-west extremity that he had described and illustrated in 

 the ' Memoirs of the Imp. Acad, of St. Petersburg ' (tomes 

 xxvii. and xxx. nos. 6 and 10, 1880 and 1882 respectively), 

 together with one of his "Dosilia (?) Stepanowvi,^^ from the 

 neighbourhood of Kharkow in Southern Russia, to which I 

 alluded in the 'Annals' of April last (p. 272), by which I 

 have been enabled, through microscopical examination, to 

 confirm all that he has stated of the forms of their several 

 spicules, especially those of the latter, of whose statoblast Dr. 

 Dybowski kindly sent me a sketch on the 30th May last, to 

 show that it possessed a tubular extension of the chitinous 

 coat, accompanied by the cirrous appendages and armed with 

 statoblast-birotules of different lengths, like those of Mr. H. 

 Mills's Carterins (olim Carterella) tuhisperma from the 

 Niagara River ; but on comparison with a mounted specimen 

 of the latter, I find D. Stcimnoum sufficiently different to 

 merit a distinct appellation. During my examination of the 

 material above mentioned I have been struck with the ability 

 and accuracy of Dr. Dybowski's observations, hence look 

 forward with much pleasure to his description and illustrations 

 of the statoblasts of his " Dosilia (?) Stepanoivii^^'' which he 

 intends to publish on the earliest opportunity. — H. J. C. 



P.P.S. — In another letter from Dr. W. Dybowski, dated 

 1st June, he sends me sketches of the statoblast of Mr. Potts's 

 Spovgilla friabilis, Leidy, var. segregata, which was also 

 found near Kharkow, in Southern Russia, thus adding another 

 locality to those already mentioned of this species. — H. J. C] 



* Dr. B. Dybowski, "Beitrjige zur iijilieren Keuntniss der in dem 

 Baikal-See vorliommenden niederen Krebse aus der Gruppe der Gamma- 

 riden/' in the Horee Soc. Entom. Boss. Beiheft zii Bd. x. p. 75, tab. x. 

 fig. 3, p. 76, tab. xii. fig. 5, p. 147, tab. iii. fig. 3 (St. Petersbourg, 1874). 



Ann. <&) Mag. N. Hist. Ser. 5. Vol. xiv. 3 



