VAN NAME: SIMPLE ASCIDIANS. 451 
Genus Tethyum Bohadsch, 1761. 
1= Styela auct. plur.]. 
34. Tethyum rusticum (Linnaeus), 1767. [Halocynthia rustica Verrill]. 
Nearly circumpolar in the Arctic Seas; northern Europe; Faroe 
Islands, Iceland, Greenland; on the American coasts south only to the 
Gulf of Saint Lawrence and Banks of Newfoundland. 
2 to 432 meters. 
35. Tethyum atlanticum, sp. nov. 
Off the coast of New England and the Middle States. 
62 to 202 (in one case 327) fathoms. 
36. Tethyum partitum (Stimpson), 1852. [Cynthia or Styela partita auct.]. 
Cape Verde Islands, western Europe, Mediterranean, Adriatic. 
Massachusetts Bay to North Carolina. Represented at Bermuda by a 
subspecies. 
Shallow water (low water to 15 fathoms only, on the American coast). 
37. Tethyum coriaceuyn (Alder and Hancock), 1848. [Cynthia placenta 
Packard, 1867; Cynthia carnea Verrill, 1871 in part; and Halo- 
cynthia tuberculum Verrill, 1879, in part]. 
Of wide distribution in northern European waters; Siberian Arctic 
Ocean; Greenland; Davis Straits. In American waters from Labrador 
and the Banks of Newfoundland to Massachusetts Bay. 
10 fathoms to 400 meters. 
38. Tethyum mortenseni Hartmeyer, 1912. 
At two American stations only, off Nova Scotia and off Cape Ann, 
Mass.; one European station (near Norway). 
45 fathoms to 660 meters. 
39. Tethyum finmarkiense (Kiaer), 1893. 
Oflf Norway. One specimen from the Banks of Newfoundland. 
20 meters to 67 fathoms. 
— . Tethyum plicatum (Lesueur), 1823. 
Philadelphia to the West Indies and South America; the Mediterra- 
nean and Adriatic Seas; Indian and parts of the Pacific Oceans; Aus- 
tralia. 
Shallow water (at least on the American coast). 
40. Tethyum molle (Stimpson), 1852. [Glandula mollis Stimpson, 1852. 
Glandula arenicola Verrill, 1872]. 
Gulf of Saint Lawrence to Long Island Sound. Tethyum vestilum 
(Stanger), 1860, of the British coasts is a very closely allied,, if distinct 
species. 
10 (or less) to 150 fathoms. (The writer has seen specimens from shallow 
water only.) 
Genus Pandocia Fleming, 1822. 
[= PoLYCARPA auct. plur.]. 
41. Pandocia fibrosa (Stimpson), 1852. [Glandula fibrosa '&i\iQY)Son, 1852]. 
