180 MR. A. W. WATERS OTS' 



wliorens the walls separating- i\\o zoopeia arc quite thin. The 

 minute structure has not heou eousidereil suffieieut to fuvuish 

 grounds for se]iaratinji- the two forms. 



The Franz-Josef Land speeiniens have 17 tentacles, which 

 seems to be about the number generally found, though Laniouroux 

 aiul Fleming, apparently in error, say 12 tentacles, Smitt gives 

 15-17, Farre IG or occasionally 15, Hiucks 15-17. I have 

 published the number of tentacles of other species, but it may be 

 well to repeat the list here. A. Ji/'rsufiim, Flem., has 15-17 

 (Hincl's) ; A. mamiUatum, 16-18 {Sincls) ; A. mytili, Dalyell, 

 15-18 (Sincks), 19 (TTafers) \ A. parasitictm, Flem., 15-16 

 {TTincl's). So that about 17 may be said to be frequently tlie 

 luiniber in yUn/onidium ; but A. duplex, Prouho, has 20 tentacles 

 (ProuJw) ; A. poJi/oiim, Hass., 20 (Hincks); A. Brncei, Calvet, 

 16-18 {Calvet) ; A. eellarioides, Calvet, 20 (C). Ilinoks gives 

 18 for A. olbidiim, Alder, whereas Pronho says about 25 ; 

 A. variegahtm, Prouho, 28 or more tentacles : A. flxisfroides, 

 Busk, 24-27 {Waters) : A.flahellifonne, Kirkp., "Kj-'IS^ {Waters) : 

 A. antarcticum. Waters, 21-27. I have sections of a small 

 subglobular specimen from Naples about | inch in dianaeter, 

 growing from a stalk and with a thick cuticula, like A.c/elafiiiostati, 

 and in some respects it seems to resemble that species, but it has 

 24 tentacles. 



In sections of specimens of A.gelatinosum from off Capo Mary 

 Harmsworth the ovarium (PI. 20. fig. 7) is siirroimded by small 

 nucleated cells forming a wall the thickness of several cells, 

 and within this are the lai'ge ova, of which there are three or 

 four. 



In tlie subglobular specimen from Naples just referred to, 

 the ovarium is in a septu-ate protoplasmic network, Avith large 

 ntfcleated ova, and this network of various shapes is distinctly 

 outlined. The ovarium is close to tlie base of the caxnim, and at 

 first has only comparativelj^ small ova, or rather embryonic cells 

 (PI. 20. fig. 8, and the upper part of figs. 9 & 10). The growth 

 of the ovarium in this species should be carefully compared with 

 that of Hornera lichenoides and other Cyclostomata. A com- 

 parison of Braem's * figure of the ovarium of Plumatella fungosa 

 shows great similarity with that of A. gelatinosnm. 



* " Die geselilechtliche Entwickehmg ron riumatcUa fungosa" Zoologica, 

 Heft 23 (1807), pi. 2. i\g. 54. 



