CLASSTPICATION OP THE TUNICATA. 617 



Ascldiozooids very long antero-posteriorly, and distinctly 

 divided into regions. 



Test of a firm gelatinous consistence. 



Branchial sac formed of a simple mesliwork of longitudinal 

 and transverse vessels. No true stigmata present. 



Dorsal la7nina represented by a series of languets. 



Gonads placed in a long postabdomen extending behind the 

 intestinal loop. 



This genus was formed for the remarkable deep-sea species 

 Pharyngodictyon mirahile, Herdm., trawled in the Southern Ocean 

 at a depth of 1600 fathoms. 



TiLOBEANCHiON *, Scrdman, 1885. 



Colony large, massive. 



Systems inconspicuous. 



Ascldiozooids large, elongated antero-posteriorly, and distinctly 

 divided into regions. 



Test gelatinous. 



Branchial sac large and well developed. Transverse vessels 

 provided with numerous large papillif orm connecting-ducts which 

 may bifurcate to form rudimentary internal longitudinal bars. 



Dorsal lamina represented by a series of languets. 



Alimentary canal large. Stomach-wall folded longitudinally. 



Gonads forming a long postabdomen. 



This genus includes the single species Tylohranchion speciosum, 

 Herdm., from Kerguelen Island. 



Glossophoettm t, LaJiille, 1886. 



Colony subglobular or expanded and lobed, attached, sandy. 

 Systems usually one in each colony, simple. 



Ascidiozooids divided into thorax, abdomen, and postabdomen 

 separated by narrow pedicles. Branchial aperture 6-lobed, atrial 

 with a lobed languet. 



Test covered with agglutinated sand-grains. 



Branchial sac with well-marked horizontal m.embranes, which 

 are denticulated or crenated so as to have a number of small 



* This genus has afRnities with Diasona and the Clavelinidae, but is, I think, 

 more closely allied to the Polyclinidce. 



t This genus seems very similar to Fleurolo^kium, Giard, 1874 (Assoc. Fran9., 

 Lille). 



41* 



