From Natural History of Southeast Alaska
|Scientific Name||Common Name||Summary|
|Ascidia callosa||Sea Blisters||This species was recently split. Reports of this species from before Gretchen Lambert's 2001 paper on the species was published were mostly referring to the similar and then synonymous Sea Blisters (Ascidia columbiana).
Ascidia callosa, however, is probably present in the region.It can be distinguished from A. columbiana in the following ways: 1: It does not have a dense circle of papillae around the siphons. Rather, its siphons look a bit like those of Broadbase tunicate (Cnemidocarpa finmarkiensis), in that they cramp up when shut and have smooth edges. 2: The edges of its tunic rolls a bit, as opposed to spreading out in a thin sheet on the edges, as in A. callosa. 3: Disection should reveal that the oviduct and sperm duct follow the inferior curve of the intestine, and does not cross it.