Mycetomorpha. 589 



tlie terminologT of Smith = the ovaiy of Delage). These are tlie 

 cells which will, judging from the case of SaccuUna, give rise to 

 the greater part of the bodj- of the adult animal. In the Cj-pris 

 they appear to be proliferatiiig, each rounded C3'toplasmic mass 

 containing a number of nuclei, as is shown in the figure. More 

 dorsally are situated lateral groups of large celLs (ph) which take 

 up little stain and appear to contain a great deal of yolk. They 

 have nuclei small in proportion to the size of the cell and are 

 possibly phagocytic in fimction. In position and general appearance 

 they correspond to the "refringent vesicles" which Delage describes 

 as the remains of the food yolk of the Sacculinid Cypris. but their 

 regularity of form and association each with a Single nucleus, lead 

 me to assume their cellular nature. In the middle line however is 

 to be Seen a nonstaining area of a granulär substance which is 

 certainl}' the residue of the yolk of the eg^. 



It must be mentioned here that though hundreds of Cypris 

 larvae were included in the series of transverse sections, microscopic 

 examination of these failed to show any with spermatozoa, developing 

 or mature. Nor were any bodies found elsewhere which could be 

 interpreted as larval males and in the face of this negative evidence 

 we must conclude for the present that the animal is parthenogenetic. 



Relationships of My ceto m o rp h a. 



No doubt can be entertained as to the inclusion of this form 

 among the Rhizocephala, but it does not come near any previously 

 described genus. Asymmetry is a feature of the group but it reaches 

 its climax in Mycetomorpha. In reviewing the genera of the Rhizo- 

 cephala, with their varying degrees of asymmetry, Smith (5, p. 12 — 18) 

 has found it possible to derive nearly all of them from the almost 

 symmetrical form Pelfogaster and a profitable comparison with that 

 genus may be made in this case too. The diftei-ences to be seen 

 betw^een Fig. L and M are mostly to be explained by supposing 

 two Chief movements of displacement. (1) a revolution through 90** 

 of the visceral mass and mesentery to the right side (with ret'erence 

 to the peduncle). (2) a subsequent curvature of the visceral mass 

 which causes the originaUy anterior mantle aperture to be directed 

 inwards, and is responsible for the formation of the bay. The ex- 

 pansion of the mantle cavity is probably at later cliange. A third 

 Clement of asymmetry is introduced by the oblique setting of the 



