28 



these specimens : »Ad insulas Fseroenses non nisi parvae eva- 

 dunt, sed exemplaria vidi in herbario eel. Vahlii, ex insula St. 

 Crucis, allata, quee ovum columbinum magnitudine exsuperant«. 

 Lyngbye referred this species to his Gastridium ovale (= Hali- 

 cystis oralis Aresch.) and G. Agardh in »Species«, p. 431, also 

 refers the specimens from St. Croix mentioned by Lyngbye to 

 Valonia ovalis and as belonging to this species it is also found 



in later authors until J. Agardh 

 described it as above quoted. 



The morphological and ana- 

 tomical organisation of Valonia 

 ventricosa has been described by 

 Murray in »Phycological Me- 

 moirs«, p. 50 and shortly by 

 KuGKUCK in Bot. Zeitung 1907. 

 As already mentioned by 

 Lyngbye the thallus of Valonia 

 ventricosa can reach a size of a 

 pigeon's Qg^, Murray says even 

 that of a hen and some of the 

 specimens I have found myself 

 also came near in size to small 

 hens' eggs. 



It is most often egg-shaped 

 or nearly globular, but sometimes 

 also pyriform or more irregular. 

 It is fastened to the substratum 

 by means of numerous small rhi- 

 zoids growing out at the basal 

 end of the plant (Fig. 16 6) from 

 the small lentiform cells occurring 

 here in great number. 



The rhizoids are unicellular 

 and end with a small, richly ra- 

 mified, often coral -hke disc (Fig. 

 16 c, d). Both the small lentiform cells and the rhizoids are 

 richly provided with starch. 



Besides the small lentiform cells, whose dianietor is about 

 250 fj. and which are crowded together at the basal end of the 

 plant, we fmd in the periphery of these crowds some larger lenti- 

 form cells. About these Kuckuck I.e. p. 180 writes: »Ausser- 

 dem werden freilich nur ganz vereinzelt zwischen den kleinen 



Fig. 16. Valonia ventricosa J. Ag. 

 a, a young plant (."jO:!). &, basal 

 end of an older plant with numer- 

 ous small lentiform cells with rhi- 

 zoids crowded at the base; to the 

 left one and above four large 

 lentiform cells, two of these again 

 with small lentiform cells and 

 rhizoids. c and d, rhizoids grow- 

 ing out from small lentiform cells 

 (fiO : 1). e, chromatophores (300 : 1). 



