VAN NAME: SIMPLE ASCIDIANS. 505 
the right ovary hes more nearly horizontal and its closed end bends 
abruptly down around the anterior end of the kidney. This last 
character appears to be one of the most constant and striking peculi- 
arities of this species. 
This animal inhabits sandy bottoms in shallow water (to 15 fathoms 
depth) from the southern shore of Cape Cod and Nantucket to and 
including Long Island Sound. It appears to live buried in the sand 
and does not attach itself to solid objects. It is local in distribution, 
but occasionally abundant in some places. 
Agassiz (1850) who first recorded this species said it was found 
"around Cape Cod" a statement that should perhaps not be taken 
too broadly, as the writer is not aware of its occurrence on the northern 
shore of Cape Cod. Stimpson (1852) gave its distribution as "the 
region of Nantucket and Martha's Vineyard." Verrill and Smith 
(1873) record it from "Long Island Sound near New Haven, [Conn.] 
3 fathoms, sand; Vineyard Sound and Buzzards Bay, [Mass.] 5 to 
15 fathoms, sand and gravel." 
In the Peabody Museum collections it is represented by specimens 
from Vineyard Sound; off Montauk Point; Gardner's Bay; Long 
Island Sound, off New Haven (Conn.) Harbor, where it was once found 
abundantly over a small area. The writer has also received a speci- 
men from Dr. Hartmeyer, which was collected in Buzzards Bay 
by Mr. G. M. Gray, and has also received from Mr. Gray a series of 
specimens from the Wood's Hole region. According to Hartmeyer, 
Molgula arenosa Metcalf (1900) is probably not this species but the 
European Caesira oculata Forbes, 1848. 
Caesira robusta, sp. nov. 
PI. 51, fig. 43-47; PI. 73, fig. 161; text-figs. 16, 17. 
The larger of the two well preserved specimens in the collection 
measures 38 mm. long, 29 mm. in height, and about 18 mm. from side 
to side, though being flattened in a somewhat oblique direction it is 
difficult to determine the exact thickness in that direction. The other 
measures 26 mm. long, 23 mm. high, and is strongly compressed later- 
ally, measuring only about 7 mm. in that direction. The siphons, 
which in the large specimen project about 5 mm., in the small one 
somewhat less, are placed quite near together, and have six prominent 
conical lobes to the branchial aperture and four lobes to the atrial 
