(1^4) 



EXPLANATION OF THE TLATES. 



Fig. 10. Tho vailiatiiig tuboj about unitiiij; latorally to , 

 Ibrm tho oiivular tiibo. Tho horn-Uko shoath i? vorv 

 oonsi>ioiious. 



Fig. K. 



Fig. K ivpTva-nts fig. 10 in mitline. n n' niiJdlo wall of the disk, in wlii>-U 

 the raiU-ttiug tuK'S ,irv hollow»\l. — ^ outor wall. — ^l outer »-all inwrtevi. 

 — Ni e\is>> of tho inversion 6'. — S- Iwttoni of the hollow formed by the 

 inversion of M. — c inneruiost wnll. thn.'>wii into profile by the prc>jection 

 of the radi.iliug tubes. — i horn-like sheath. — i diwrticuU ft«m the 

 radiating tubes to form the oiivular tube- 

 Fig. 11. Tho oiivular tiiW is just fonnoil by tho UitonJ 

 juuoiiou ot" tho railiatiug tuK\<, Tho toutaolos Ivgin 

 to Iv pwuiinout. 



Fig. L. 



F^. L repro5«-nts fig. 11 in outline. <i r.i the middle wall, in which the 

 radiating tulv* atv hollowed.— .:' in profile in the plane of the axis. — 

 b outer w^l of the disk. — .-^ outer wall at the point of involution. — c 

 c^ iunemnvt \r\ll. — .' citvular cau,al. — r- jnnoliou of the radiating and 

 circular canals. — » the prv>boscis. — o the iuciiiii'nt tentacles. 



Fis;. 1-. Tlio oiivular tulv is oomploto. tho transvorse 

 voil is <listiuotly tluvo walUnl. and tho proKisois is 

 qiiito largo, but it occupios still a oomp;irativol_v largor 

 part of tho oavity of tho Kxly than aJtorwanls, aud 

 is irlobular. 



Fig. M rvpivsents fig. 12 in outline. This figure is a combination of a pro- 

 file .^ud a surfiu-c view, the radi.iting tubes being ne-ircst to the eye. a 

 outer wail of the disk or i>e>licel. — n' outer wall of the tentacles. — o- 

 coutinuation of a and <i^ along the etisy of the disk. — a^ where at and 

 n- meet. — rt* convsi»ouds to o-, iu profile, — a^ outer wall of the veil, 

 heiv seen in profile, in the distance. — A the point of the innermost 

 wall, in prv>file. which corresponds to r-\ — b the middle wall of the disk, or 

 inner wall of the i»e\licel. — 6i the .same as 6 but nearer the eye, and hol- 

 lowe>1 out by the radtiting can.il. — i^ inner wall of the probA«cis contin- 

 uous at b* with 6. — £►< the middle wall of the veil, continuous with i. — 

 b* origin of the radiating canals b^. — i^' circular caual. — c the outer and 

 inner outlines of the iunennost wall. — c' the outer wsll of the proboscis 

 at cS continuous with c. — c* the innermost wall of the veil in profile. — 

 c^ the same as c* but nearer the eye. — ct the circular tube cut across in 6. 

 — i thehoru-Uke sheath, which completely inclivses the mevlusa. 



Fig. 13. Shows tho tontaclos (a') boforo thoy aiv curlod 



into tho oavity of tho disk. 

 Fig. 14. Tho tontaolos highly dovolopod, and ourlod 



iuwarvily, fon'ing tho transvoi-so voil into tho oavity 



of tho disk. 



Fi;:. X lepresents fig. U in outUne. Although the tentacles are curled in- 

 war\lly. they are shut off from the cavity of the disk by the reil ifi r*). 

 11 the outer wall. — r the inner wall of the pedicel, or middle wall of the 

 disk, and containing the radwtiog canals. — M the bulbous cavity of the 

 tentacles. — N^ inner wall of the proboscis, continuous with d. — c the 

 innermost wall- — ri outer wall of the prob<veL?. continuous with c. — c2 

 j^riphery of the veiUi-^i. — c^ point of union of c and ct- — c* the veil- 

 — <:' the tentacular bulb- — ? the eye-speck- — /' the tentacles, — ^ the 

 future di::estive cavitv- — i the horn-like sheath- 



