VAN NAME: COMPOUND ASCIDIANS. 385 
Didemnopsis tenerum (Verrill). 
Text-figs. 16, 17; PI. 39, fig. 15. 
1S71. Lissoclinuin teneriim Verrill, Amor. Journ. Sci., ser. 3, vol. 1, p. 445. 
1872. Lissodinum tenerum Verrill, Amer. Journ. Sci., ser. 3, vol. 3, p. 212. 
1879. Lissodinum tenerum Verrill, Preliminary Check-list of Marine Inverte- 
brata, p. 27. 
1891. Lissodinum tenerum Herdman, Journ. Linn. Soc. London, Zool., vol. 23, 
p. 629 (listed as uncertain species). 
1909. Lissodinum tenerum Hartmej^er, Bronn's Tier-reich, vol. 3, suppl., 
pp. 1453, 1456 (mentioned as uncertain species). 
Professor Verrill's type of Lt-t.'iorh'ninn trucrum was among the 
specimens of this animal examined. Didemnopsis variahiJc (Huitfeldt- 
Kaas), 1S9G, is very probably identical with this species. Its synon- 
ymy is as follows: 
1851. Didemnum gelatinosum (err., non Milne-Edwards, 1841) (part) Sars, 
Nyt Mag. Naturvidensk., vol. 6, p. 154. 
1858. Didemnum gelatinosum Sars, Forh. Videnskabs-Selsk. Christiania, p. 66. 
1892. ? Pseudodidemnum sp., Herdman, Proc. and Trans. Liverpool Biol. 
Soc, vol. 6, p. 91. 
1896. Didemnoides variahile Huitfeldt-Kaas, Norske Nordhavs-Exp., Zool., 
vol. 23, no. 1, p. 5, pi. 1, figs. 1,2. 
1903. Didemnopsis variahile Hartmeyer, in Romer and Schaudinn, Fauna 
Arctica, vol. 3, p. 366, pi. 6, fig. 19; pi. 14, fig. 22. 
1904. Didemnopsis variahile Hartmeyer, Wiss. Meeresunters., Abt. Helgoland, 
vol. 5, pt. 2. 
1905. Didemnopsis variahile Bjerkan, Bergens Mus. Aarbog, no. 5, p. 22, 
pi. 3, fig. 9. 
1906. Didemnopsis variabile Redikorzew, in Derjugin, Die murmansche biol. 
Station, Trav. Soc. Nat. St. Petersbourg, vol. 37, p. 155. 
1907. Didemnopsis variabile Redikorzew, Ann. Mus. Zool. Acad. Sci. St. 
Petersbourg, vol. 11, p. 151. 
1907. Didemnopsis variabile Redikorzew, Zool. Anzeiger, vol. 31, p. 522. 
1908. Didemnopsis variahile Bjerkan, Tromsoe Mus. Aarsheft., no. 25, pp. 
101, 115. 
1908. Didemnopsis variahile Redikorzew, Trav. Soc. Nat. St. Petersbourg, 
vol. 39, pp. 21, 36. 
1908. Didemnopsis variabile Redikorzew, Mem. Acad. Imp. Sci. St. Peters- 
bourg, ser. 8, cl. phys.-math., vol. 18, no. 11, p. 49, fig. 11. 
1909. Didemnopsis variahile Hartmeyer, Bronn's Tier-reich, vol. 3. suppl., 
p. 1447. 
"Colonies incnisting shells, ascidians, etc., forming thin soft gelati- 
nous crusts, which are translucent and filled with numerous very small 
