500 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
the ovaries were greatly developed and distended with eggs of various 
sizes, while the testes were comparatively small, in respect to both 
the number and the size of the pyriform or lobed glands which com- 
posed them. The eggs when ready to be laid are rather large, 0.26 
mm. or more. They develop into tailed larvae in the peribranchial 
cavity. A group of these tailed larvae was usually present in the 
peribranchial cavity on each side of the body near the gonad. The 
larvae in these groups generally measured about 0.36 mm. long exclu- 
sive of the tail, but larger, more advanced ones were also sometimes 
present, generally in other parts of the cavity. 
Left gonad situated dorsal to the intestine (nearer the reflected 
part of the loop than to the rectum); the right, dorsal and anterior 
to the kidney. The ovary is elongated, bent in an inverted U-shaped 
curve. The opening is downwardly directed and at the anterior end, 
and is not produced into an oviduct. The testis consists of a series 
of small pyriform or more or less lobed glands bordering the posterior 
margin of the ovary or overlapping and covering it in part. 
In the New England region this species occurs from the Gulf of 
Saint Lawrence (Whiteaves, 1874, 1901, identification by Verrill) 
and Bay of Fundy to off Martha's Vineyard, chiefly in depths of 10 
fathoms or more (70 fathoms being the maximum recorded), preferring 
stony, shelly, or sandy bottoms. Verrill (1871a) reports it from 
Eastport, Me., at low-water mark under stones, and off the northern 
side of Treat's Island, in 10 to 20 fathoms in shelly bottom. Verrill 
and Smith (1873) give its distribution as follows: 
"Off Martha's Vineyard, 10 fathoms, stony; Casco Bay and Bay 
of Fundy, 10 to 20 fathoms." 
The writer has examined specimens from 
Eastport, Me. (including Professor VerriU's types). 
Casco Bay, Me. 
George's Bank, 50 fathoms. 
Station 372 (21 miles east of Chatham, Mass., N. lat. 41° 40', W. long. 69° 
28' 30", 70 fathoms, sand and pebbles). 
Station 2080 (N. lat. 41° 13', W. long. 66° 21' 50", 55 fathoms, gray sand). 
Its distribution is really much wider, for there can be no doubt of the 
identity of Traustedt's (1883) Molgula tenax with the present species. 
Examination of a specimen of C. tenax kindly sent by Dr. Hartmeyer, 
confirms this conclusion. The largest specimen mentioned by Hart- 
meyer is 16 mm. long, somewhat larger than any the writer has exam- 
