128 NOTES ON THE ANATOMY OP DINOPHILUS. 



these structures open into the portion of tlie body-cavity which un- 

 doubtedly surrounds them. In some cases the appendage appeared 

 distinctly bifid (fig. 15), whilst in others it had a fimbriated appear- 

 ance, and seemed to be composed of a large number of minute, elon- 

 gated, pear-shaped bodies, each attached by its narrow end to the 

 point where the appendage as a whole passed into the excretory por- 

 tion of the tube. These minute bodies vibrated individually (i. e. 

 not in connection with their neighbours) in the body-cavity space in 

 which they were situated. These observations do not appear to 

 favour the view that the ciliated appendage contains a single vibra- 

 tile flame, nor indeed to render it easy to suppose that the appendage 

 opens into the body-cavity. 



At the same time, it must be noted that the ciliated appendag-es 

 of the first nephridia are somewhat larger than those of the other 

 nephridia, and that several observations were made which seemed to 

 show that the appendage did really open into the body-cavity. In one 

 of these cases I believed that I could see the individual cilia of the 

 appendage projecting into the body-cavity. It is not impossible that 

 the anterior nephridia have attained a somewhat higher degree of 

 differentiation than the remainder. 



The proximal end of the excretory portion, into which the cilia of 

 the appendage project, as above described, does not seem to be 

 ciliated, whilst the lumen of this region of the nephridium appears 

 to be often in the condition of a series of isolated vacuoles rather 

 than of a single passage continuous with the cavity of the rest of the 

 organ. Cilia make their appearance towards the end of the pig- 

 mented portion, and can be followed uninterruptedly, from that 

 point, as far as the external aperture. The " duct ■" has extremely 

 delicate, colourless walls, and, as just stated, is richly ciliated in- 

 ternally. 



Generative Org^ans. — a. Male. — The testes consist at first (as is 

 shown by the examination of young individuals) of minute, paired, 

 linear cords of cells (fig. 11), lying on the ventral side of the stomach 

 in the general connective-tissue of the body."^ It appeared probable 

 that the testicular cells were simply differentiated connective-tissue 

 cells. Owing to an injury to the tail end of the individual from 

 which fig. 11 was drawn, it could not be ascertained whether or not 

 a penis was already developed. 



At a slightly later stage the cords of cells which constitute the 

 young testes are found to have become slightly expanded in a lateral 



* It is not impossible that this and the next stage described may really be young con- 

 ditions of the female generative organs, and that, for instance, the structure described as 

 the penis may be the unpaired oviduct. I believe, however, that I am right in identifying 

 the animals in question as young males. 



