VAN NAME: SIMPLE ASCIDIANS. 441 
some of the species recorded by Lesueur, Couthouy, and Gould (see 
above). 
Agassiz (1850) describes seven new species from the shores of Massa- 
chusetts. His descriptions are very brief and unsatisfactory, and his 
types are not known to the writer to be in existence. Professor Verrill, 
who was one of Agassiz's students, has informed the writer that these 
types were probably never preserved at all. Agassiz had colored 
drawings of them prepared by an artist (Mr. Burkhardt), but did not 
publish these drawings. They were used years afterward (1870) 
by Binney to illustrate the second edition of Gould's " Report on the 
Invertebrata of Massachusetts," and with their aid it has been possible 
to determine what Agassiz's species are. The list is as follows: 
Ascidia amphora, sp. nov. = Caesira manhattensis. 
psammophora, sp. nov. = " arenata. 
ocellata, sp. nov. = Ciona intestinalis var. ocellata. 
carnea, sp. nov. = Dendrodoa carnea. 
hirsuta, sp. nov. = Pyura echinata. 
rugosa, sp. nov. = Tethyum partitum (probably). 
Boltenia microcosmus, sp. nov. = Pyura ovifera. 
Two of Agassiz's specific names are still retained, while four of the 
others are synonyms of previously described species. The remaining 
name (Ascidia psammophora) the writer, following Verrill, rejects on 
the ground that it is insufficiently described. The species is determin- 
able only by Burkhardt's drawing, while long before the drawing 
was published, Stimpson (1852) had published a recognizable descrip- 
tion of the species as Molgula arenata. 
Stimpson (1851) described as a new species from Massachusetts 
Bay: 
Pelonaia arenifera, sp. nov. = Pelonaia corrugata. 
In 1852 he described from the Bay of Fundy region : 
Ascidia callosa, sp. nov. = Phallusia prunum. 
" tenella, sp. nov. = Ciona intestinalis var. tenella.' 
" geometrica, sp. nov. = Chelyosoma macleayanum. 
Glandula fibrosa, sp. nov. = Pandocia fibrosa. 
" mollis, sp. nov. = Tethyum molle. 
Boltenia rubra, sp. nov. = Pyura ovifera. 
From George's Bank: 
Pera pellucida, sp. nov. = Caesira crystallina. 
