114 Proceedings of the Royal Irish Academy. 



and apparently non-retractile tentacles leave a fairly wide clear space round 

 the mouth, with its finely ridged lip; the inner ones are large, and are 

 attached to the disc by a narrow neck, above which they suddenly swell out 

 bulbously, then gradually taper oil' to a Muni point. Hound the "neck," and 

 below the swollen part, is distinctly visible a circular suture, and this is the 

 ''line of breakage" of the tentacle Some of the tentacles ar# neatly broken 

 off at this point, and in these the tentacular sphincter 'which lies just above 

 the neck, and is thrown "11 with the tentacle i is clearly visible as a thin 

 circular veil, projecting across the lumen of the tentacle, and almost block- 

 ing it. The tentacle.- are still', thick-walled (in their present state of con- 

 traction), self-supporting, and distinctly longitudinally fluted. They area 

 good ileal smaller in proportion to the size of the body than in typical 

 ; A', longieornis, at any rate. Outer tentacles much smaller 

 than inner. Radii of oral disc not well marked, save among the tentacles. 

 Two actinopharyngeal grooves. Whole animal flesh-coloured in spirit, 

 actinopharyns darker. Tentacles in .*. cycles — 12 + 12 + 24 + 48 + ca. 60 



1 56. 



(ii) The othei specimen is similar, but ha- lost nearly all its tentacles, 

 and has the body more pulled out ami the wall, in consequence, thinner and 



more flaccid. Tl ral disc, moreover, has the same diameter as the pedal. 



These are only differences which a living specimen would be able to alter 

 constantly. Tent.; in about 4 cycles. 



s S men < 1 » has 77 pairs of mesenteries, of which 4~> pahs 



perfect The development is somewhat irregular — the first .".cycles are 

 perfect in varying i the primal \ mesenteries being joined to the 



actinopharyns throughout its length, the secondaries running down it less 

 tar. the tertiaries siill lees; the rest do not reach it at all, and this 4th 

 imperfect cycle is not yet fully formed. In one Bector of the animal specially 

 examined, the primaries appeal- sterile, the secondaries have small gonads, 

 and the other in- are very fertile. 



3 cimen (ii) 77] s of mesenteries in 4 cycles (13p. + I3p. + 25p. 



- -or. 77. i The first 3 cycles are perfect to a varying extent, and here the 

 4th-i yele mesenteries also ju.-t reach the actinopharynx. (I have shown 



ioii.-lv that in B. !•■ ■ tie- last cycle may or may not be 



perfect.) Primaries sterile, at any rate some of them, the others fertile. 

 Tin' mesenterial development is irregular, some of the 3rd-cycle mesenteries 



on on,- aide of the '■■• ••!> being no larger than 4th-cycle ones on the other, ami 

 the 4th cycle being incompletely formed. Both internal and external stomata 

 lit. 

 (iiii It is interesting to note that in a specimen of this g] ies from the 



