A. General Works. 3 



ciilaire peut-etre identique ä la chlorophylleff. It is reserve-granules that lead to 

 the innumerable variations of colour in Leucosolenia coriacea. Stylinus columella 

 lias the remarkable peculiarity of forming in its » cellules sphernleuses « granules 

 of carbonate of Urne, which give to the sponge its opaque milky appearance. »Le 

 carbonate de chaux est ä ajonter ä la liste des matieres de reserve qu'emmagasi- 

 nent les Eponges«. In Buharis verticillata the »cellules sphernleuses« are in part 

 small, containing colourless spherules, in part large, containing spheriiles of 

 a garnet-red. The other cells of the sponge are yellow, and the colonr of 

 the mass varies from yellow to bright orange according to the amonnt of 

 cell Contents in the large spherule-bearing cells. In Raspailia ramosa at Luc 

 the colour of the spherules is dichroic green and red, the other tissues are 

 yellow, the general effect is »brun fonce«. But at Roseoff the sponge is rarely 

 brown, the cellules sphernleuses being generally colourless. Starch is re- 

 corded in the spherule-bearing cells of three species of Reniera. — Cuticle. 

 A distinct cuticle can be detached from the surface in Cliona celata, Suherotelites, 

 and Stylinus columella ; Hymeraphion coronula has a viscous surface and Reniera 

 viscosa secretes »une mucosite abondante«. — Spicules. In Halichondria inops 

 the spicules contain »un large canal axial presque constamment rempli d'air«. In 

 Esperella littoralis isolated raphides were found in cells apparently ectodermal ; it 

 is suggested that possibly they originate separately. Of spicules in general, they 

 are, when all is said, the most certain basis of Classification. — Larvae. The 

 larvae more superficially situated in the mother are often more highly pigmented 

 than those in the deeper parts of the body ; the spiculation also apparently varies 

 [Hymeraphia echinata) according to the region in which the larva is produced. 

 The principal spicules of the skeleton rarely appear until after fixation ; on the 

 other band many larvae have spicules the production of which ceases when fixation 

 is complete. — Efferent canals. The curious process of » decollement « in the 

 Walls of the efferent canals oi Pachymatismajoknstonia (already described 1890) 

 tends »Sans doutecf by diminishing the calibre of these canals )jä augmenter la 

 vitesse et la force du courant d'exhalation«. 



Grentzenberg finds in the Baltic Sea 15 species of sponges. Some more or 

 less new anatomical details are given of Halichondria panicea, Reniera aquaeductus 

 and varians, Chalinula ovulum SLiid/eriilis^ Chalina limhata^ Pachychalina rustica, 

 Esperella lanugo. 



Hanitsch mentions 10 species of sponges from the West Coast of Ireland. 

 Some anatomical details are given of Esperella sordida (with larvae) and Aplysilla 

 rubra, the latter name being used instead of Halisarca rubra , as the sponge was 

 erroneously called in 1890 [cf. Bericht f. 1890 Porifera p 3]. 



Keller C^) attempts to give a mechanical explanation of the various types of 

 the skeleton. Such forms as Euplectella are especially suited for life in deep 

 water; they can stand a considerable , though not very variable pressure, while 

 sponges which live near to the coast in shallow water , must be more elastic in 

 Order to stand the effect of the surf. A more elastic skeleton is thus wanted than 

 a purely siliceous network can ever exhibit. The material herefore is found in 

 the spongiü. The author's conclusion is, that »die mechanische Ursache, welche 

 zur Sponginbildung und damit auch zur Entstehung und Weiterentwickelung der 

 sponginführenden Monactinelliden und Hornschwämme führte , in dem bewegten 

 Wasser mit seiner starken Beanspruchung auf Druck und Zug zu suchen ist «. 



Murray & Irvine found that »although universally distributed over the ocean's 

 floor, the spicules of sponges rarely make up over 1 or 2 per cent of a deep-sea 

 deposit, except in those limited areas where there are extensive patches of these 

 sponges growing on the bottom , when the spicules in some samples of a deposit 



