,ü30 I. IKEDA : 



exterior. However, it seems elear to ine tlmt tliis eord is nothing 

 else than an early stage of the intestinal ontgrowtli independently 

 produced at the posterior end of the gnt. Moreover, in Phoronis 

 ijimai, the gut cavity does not eonie into eoinnninication with the 

 exterior at so early a developmental stage as Caldwell observed ; 

 in that species, the anus first opens at a definite stage when the 

 larva l)ears two pairs of larval tentacles, 



E. SciTULTZE ('97) rejects Caldwell's views in regard to 

 the anal ])it, ]»ut regards it as a rudiment of the future ventral 

 ])Ouch of Actinotrocha. This is, however, certainly not true, since 

 the ventral ])oucli is a thing that has a distinct origin and appears 

 at a much later stage of larval development. 



<J. Further Observations ox the 



])EyELOrMENT OF TUE LaRVA. 



Rome authors have recorded that the larva swims about 

 abroad at such a stage of development as is rcj-a'csented in fig. <S. 

 However in Phoronu iju/ifii, the larva lies hidden in the lop- 

 hophoral loops of the mother until it has acquii'cd at least two 

 pairs of larval tentacles. 



In the larva shown in fig. 9, the somewhat ])rominent preoral 

 lobe hangs over the larval month. Local ectoblastic thickenings 

 occur at two places, ?;/-., at the centre of the upper surface of 

 the ])reo]-al lobe and along the mid-ventral line near tlie posterior 

 end of the bod3\ The former is the future nerve ganglion ; the 

 latter, the rudiment of the first pair of larval tentacles. The 

 nephridial invagination at the posterior end is still shallow. 



At a little later stage, the tentacular thickening divides into 



