30 MCMURRICH. [VoL. III. 
rudimentary nature of this last cycle is also evidenced by the 
absence of a fifth cycle of tentacles, there being usually one 
cycle of tentacles more than mesenteries. I do not think that 
the small size and incompleteness of these mesenteries are due 
to the specimens examined being young, but rather imagine 
that there is a tendency towards the disappearance of this cycle 
in this form. 
The inner mesenterial stomata only were observed. The 
muscle bundles, both longitudinal and parieto-basilar, are pres- 
ent, and fairly well developed. In one specimen examined, one 
mesentery of a pair belonging to the first cycle had longitudi- 
nal muscle fibres equally well developed upon both its surfaces, 
the parieto-basilar being absent, and a greater portion than 
usual of the surface of the mesentery was covered with muscle 
fibres. The reproductive organs are borne by the mesenteries 
of the first and second cycles (Pl. III., Fig. 10), with the excep- 
tion of the directives. On some of the mesenteries of the 
second cycle they were absent; but no regularity was apparent 
in their occurrence or absence on different mesenteries of the 
cycle. 
This form seems to resemble in some respects Bunodes stella, 
Verrill (64), and I regret that my efforts to obtain specimens of 
that species for comparison were unsuccessful. Andres ('83) 
places it among the “ Bunodidz incerto sedis,” being uncertain 
whether to consider it a Bunodes, Phymactis, or Aulactinia. 
Perhaps further investigation will demonstrate the identity of 
the two forms, in which case they should both be included under 
the name Avdlactinia stella. 
In placing Az/actinta among the Bunodidz, the importance 
of one of the fundamental peculiarities of the family as defined 
by R. Hertwig (82), viz., the presence of numerous perfect mes- 
enteries, has been lessened. I was at first inclined to separate 
Aulactinia from the Bunodidz on account of the small number 
of perfect mesenteries which they possess, but further consid- 
eration showed the inadvisability of such a classification, since 
in other important features, such as the presence of a strong cir- 
cumscribed endodermal muscle, of reproductive organs on the 
mesenteries of the first cycle, and in the absence of cinclides 
and acontia, there is agreement. The small number of perfect 
mesenteries does not seem to be a character of sufficient impor- 
