488 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
Kidney a rather elongated sausage-shaped sac of considerable size, 
situated against the mantle in the right postero-ventral part of the 
body. Its concave border is directed dorsally and somewhat forward. 
Gonads proportionally rather short and broad, consisting of a 
central elongated ovary abruptly bent or curved dorsally, bordered 
by the numerous small, irregularly disposed, pyriform or lobate testes. 
The testes extend also to a considerable extent in between the ovary 
and the mantle partially concealing the ovary when the gonad is 
looked at through the mantle. On the left side the gonad lies dorsal 
to the intestine, the testes in its lower portion, however, extending 
down to some extent between the intestine and the mantle. On the 
right side it lies dorsal and somewhat anterior to the renal organ. 
Most of the specimens in the collection came from Eastport, Me., 
and Grand Manan, N. B., and other places in that vicinity, where 
the species is common, occurring, according to Professor Verrill 
(1871a) on muddy and shelly bottoms in depths from 10 to 80 fathoms. 
It is also represented by large specimens from Casco Bay, where it 
occurs on muddy bottoms in from 2 to 64 fathoms (Verrill, 1874a) 
and by several of various sizes from near the eastern edge of George's 
Bank (Station 2525, N. lat. 41° 49', W. long. 65° 49' 30", 72 fathoms, 
sand, gravel, and broken shells). Two examples from Murray Bay, 
Gulf of Saint Lawrence, collected by J. W. Dawson, incrusted with 
coarse sand, were poorly preserved, but apparently of this species. 
Whiteaves (1874, 1901) records it from Orphan Bank, Gulf of Saint 
Lawrence. This species is evidently a close ally of C. septentrionalis 
(Traustedt) described above (p. 478). 
Caesira citrina (Alder and Hancock). 
Pi. 48, fig. 26-30; PI. 73, fig. 163; text-figs. 10, 11. 
1848. Molgula citrina Alder and Hancock, Trans. Tyneside Nat. Field Club, 
vol. 1, p. 198. 
1850. Molgula citrina Cocks, Rept. Cornwall Polyt. Soc. for 1849, p. 73. 
1869. Molgula ci'rina Norman, Rept. British Assoc. Adv. Sci. for 1868, p. 303. 
1871. Molgula littoralis Verrill, Amer. Journ. Sci., ser. 3, vol. 1, p. 56, fig. 4a. 
1871. Molgula nana Kupffer, Berichte Komm. d. Meere, 1871, p. 136. 
1872. Molgula littoralis Verrill, Amer. Journ. Sci., ser. 3, vol. 3, p. 211. 
1874. Molgula littoralis Whiteaves, Amer. Journ. Sci., ser. 3, vol. 7, p. 7. 
1879. Molgula littoralis Verrill, Preliminary Check-list of Marine Inverte- 
brates, p. 27. 
