DESCRIPTION OF THE PLATES. 



123 



Opsonij-oplax in tentacles, nr .... 

 " band in circumoral face, m^ . i 



" in anchor, m^ .... 



" " partitions, m' ... 



" " peduncle of anchor, ni" 



" " in proboscis, wi" 



23. Opsophrap^ma in umbel, n (04.15, the face ; 'fpayfia, xcall) 



" " tentacle, n' . 



" " anchor, ?r . 



" " proboscis, n' . 



24. Oomyoplax (uov, an eijg ; pvj, muscle; nxaj, a latjrr) . 



25. Probosci.s, p . 



" mouth, p^ . 



" (buccal) cavity, p^ . 



" base, p' . . . . . 



" buttresses (see circuiuorul buttresses) 



26. Peduncle, r ..... . 



" sheath, r' . 



" junction with unilicl, t" . . . 



" canals (camera-), t' . 



" " entrance to, t* . . . 



" " anastomoses, r^ . . . 



" furrows, r" . 



" muscles (sec 30) .... 



2T. Spermatozoa, p ..... 



28. Tentacles, ■}> . . . . . 



shaft, t' • • • • • 



" spheroidal tip (uema;tocystophore), <}>'' 



" cavity, 4>' . 

 " neck at base of, <f-, ^' . . . 



29. Umbelhi, 4 ..... . 



" cavity (camera;), 4' . . . _ .: 



" partitions, 4°; pro.ximal end, 4-' . . 



" margin, 4^ . 



" angles, 4* . 



" post-buccal cavity, 4''' ... 



" i)assagc-ways between cameras, 4' 



30. Uromyoplax, r (oupa, a tail; five, musele ; rtXal, layer)*- 



" extension along caudal disk, »■' . 



" along (4") post-buccal cavity, r- . 



" fibres of, r' .... 



31. Yibratih^ cilia, co . . . . . 



*' 111 fig. 25, o^ slionM be a^ ; in fi^. 2u, «' sliouM be a"^ ; in fig. 27, ti^ siioul 

 *2 In figs. 47«, 4!), .lud fiO, Iho euyraver lias eiToueously useil y an 1 j', inste 



T4, 



59, 



59, 



1 of )■ au.l rK 



PLATE I. Figures 1 to 17. 



Figures 1 to IG, IlalicUjslus auricula Jas. Clark; natural size and various altitudes and ages. 



rig. 1, profde view, the umbclla turned backward. Figs. 2 and 3, anterior face, tlie arms in two 

 attitudes. Figs. 4 and 5, two profile views with the umlielhi thrown forward. Fig. G, the nmbella 

 folded acro.ss the middle, and two opposite halves brouglit near together, face to face. Fig. 7, the 



