11 OCCURRENCE 69 
3 cm.—it is of a bright red colour. (4) Fritillaria, Q. and G., in 
which the body is elongated (Fig. 52) and composed of anterior 
and posterior regions, the tail relatively short, the endostyle 
Fic. 31.— Transverse 
section of body and 
tail of Otkopleuwra 
Jlabellum (?) at, 
Atrial tube; 0/.s, 
blood - space ; 47.s, 
cavity of pharynx 
or branchial sae ; 
ec, ectoderm; en, 
endoderm 3; ep.p, 
epipharyngeal cili- 
ated bands ; gel, 
gelatinous layer be- 
tween ectoderm and 
endoderm ; hy.p, 
hypopharyngeal 
ciliated band ; mus, 
muscular tissue on 
inner surface of 
ectoderm of tail; 
nm, nerve-cord ; 7’, 
its continuation in 
the tail ; n.ch, noto- 
chord in tail; 7, 
rectum ; sg, one of 
the stigmata or cili- 
ated openings from 
the branchial sac to 
the atrial tube; ¢, 
test (= young ‘‘house”); 2, bridge of gelatinous tissue in front of stigma closing 
branchial sac off from atrial tube. (After Herdman.) 
recurved, the stigmata opening far in front of the anus, and an 
ectodermal hood is formed over the front of the body. 
In all nearly forty species of Larvacea are known. 
Occurrence.—Although for the most part transparent, and 
usually almost invisible in sea-water, some Appendicularians may 
have certain parts of the body (alimentary canal, endostyle, 
gonads, etc.) brilliantly pigmented (orange, violet, etc.), and may 
under exceptional circumstances be present in such profusion as 
to colour tracts of the sea. Appendicularians are widely dis- 
tributed, having been found in all seas from the Arctic to the 
Antarctic, both round coasts and in the open ocean. Although a 
few species have been found at considerable depths in the 
Mediterranean, still in the Atlantic they are not deep - water 
animals, and as a group must be regarded as surface-forms. 
They are fairly abundant to a depth of 100 fathoms, and some 
few reach 1500. Species of Ockopleura and Fritillaria are 
