123 
ON PHOEONIS OVALIS, STEETHILL WEIGHT. 
lophophore was being regenerated were found in certain 
colonies. 
On p. 164 of his monograph, de Selys-Longchamps makes 
the significant remark that it is difficult to believe that the 
numerous individuals which compose a colony of P. ko wa- 
le v sky i can have been derived from as many Actino- 
trocha larvae. It seems most unlikely that these larvae, which 
lead a pelagic existence, can assemble at the time of their 
metamorphosis in sufficient numbers to build up a colony of the 
kind characteristic of this and other species. Allusion is made 
to the observations of Cerfontaine, who found numerous re- 
generating fragments in colonies ofPhoronis which appeared 
to be dead and decomposing ; and toothers by Ikeda (1901, 
p. 580), who had found young animals which he supposed — 
probably wrongly — to have been derived from larvae, in the 
debris of old colonies. De Selys-Longchamps believes that 
fragmentation of the individuals is a normal process, and, as 
this is followed by regeneration of the pieces, that it is a 
method of asexual reproduction. The correctness of this con- 
clusion is borne out by my own observations on P. oval is. 
Specific Characters of Phoronis ovalis. 
It has already been pointed out that P. ovalis has not 
hitherto been recognised since its original description by 
Strethill Wright in 1856. As doubts have been cast on its 
claim to be regarded as an adult form (cf . de Selys-Long- 
champs, 1907, p. 188), it is important to notice that the 
Northumberland material includes specimens possessing fully 
developed ovaries (PI. 7, fig. 2) or testes. The following* 
diagnosis of the species may be given : 
Size very small compared with that cf other species of the 
genus. 'Total length reaching at least 6 mm., the diameter of 
the body being about 250 p, and of the tube, in large 
specimens, about 250-350 ju. Tube delicate, hyaline, em- 
bedded in the substance of shells of molluscs. Lophophore 
oval, not much broader than long, one of the longer sides of 
