PHYSIOLOGY OF SPONGES. 319 



d'or, etaient en 6tat d'elaboration sexuelle tres active (mois de Janvier)/' In 

 the St/con raphanus of the aquarium, with which I mostly worked, I never 

 remember seeing any golden-yellow pigment, so that I am unable to do more 

 than transcribe the passage. 



Note D. — The Faces of Sponges, and Phagocytosis (pp. 306, 310). 



The fact that Dendy occasionally found in inhalant canals the " small 

 masses of granules" which he describes and figures (1914, p. 365, fig. 93) 

 does not discredit my interpretation of them (1895, p. 18, fig. 13 a) as being 

 feces. It is obvious that, even in the sea, the feces of another sponge may 

 often drift into the afferent system ; but the sponge from which Dendy drew 

 his tig. 93 was examined two or three hours after it was collected, and was 

 watched in a glass dish where " there was an active current issuing from the 

 vent, bringing with it a quantity of fine yellowish-grey sediment, which 

 collected at the bottom of the glass dish" (1914, p. 320). In that small 

 volume of water any particles carried out in the oscular stream, which were 

 too small or light to sink rapidly, would be borne again back into the sponge 

 through the inhalant canals. 



That they are not spermatozoa is proved by my finding them in the three 

 winter months, to which that part of my work on the living Grantia 

 compressa was limited. I found (1895, p. 11) that this sponge is annual at 

 Plymouth, larvae being recorded in May and July, and only the young sponges 

 produced by them being found in September, when there are none but minute 

 individuals. Dendy rediscovered this, and considers that the breeding-season 

 " would seem to begin in the first half of April," when " comparatively few 

 embryos are found" (1914, p. 321), his visit to Plymouth being April 10th 

 to April 22nd. My friend Professor Dendy will therefore agree with me 

 that a drawing (1895, fig. 13 a) made on Feb. 7th was not from a huge swarm 

 of spermatozoa, and my first observation of these faecal agglomerations was 

 in December. [For breeding-time see also Orton (1920) pp. 340, 341.] 



These extremely large masses were met with in sponges which had been 

 subjected to experiment in regard to their endurance of low-tide conditions, 

 and it is worth remark that the sponge from which Dendy'sfig. 93 was drawn 

 had been gathered about mid-day April 18th, 1912 (1914, p. 320), and 

 therefore at dead low-tide, the day before an exceptionally deep spring-tide. 

 It is obvious that in sponges which have been out of the water for many 

 hours the cellular excreta from the collar-cells, if there be such excreta, 

 must accumulate for all those hours in the flagellate chambers, instead of 

 being steadily thrown out in the normal way through the oscular stream as 

 described by Bowerbank (1858, p. 121)* and others. There is, therefore, 

 prima facie reason for supposing that any finely granular substance found to 



* Compare also 1857, last paragraph but one (p. 15 of the reprint) : — " If the sponge " 

 some time after feeding with indigo " be now removed into fresh water, the ejection of 

 molecules of indigo continues for hours to be slowly effected." 



24 



• 



