448 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
Distribution. 
The region with which this paper deals, extends from the Gulf 
of Saint Lawrence and the Banks of Newfoundland southward to, 
and including. Long Island Sound. In the brief synopsis of distribu- 
tion of the several species here given, the species are numbered con- 
secutively from 16 onward, numbers 1 to 15 inclusive being compound 
ascidians described by the writer in a previous paper (1910). Deep- 
sea or extra-limital forms that are described in this paper are included 
in this synopsis, but are not numbered, and to prevent confusion, 
the names used by Verrill and other American writers are often given 
in brackets following the name here adopted. The records of the 
Peabody Museum give many localities for some of these species which 
the writer could not verify. They have not been quoted in this 
paper, nor have they been depended on in working out the distri- 
bution of the species, for they were generally made out after merely 
superficial examination of the specimens and contain many errors of 
identification. 
Family CAESIRIDAE Hartmeyer, 1908. 
[= MOLGULIDAE auct. plur.]. 
Genus Bostrichobranchus Traustedt, 1883. 
16. Bostrichobranchus pilularis (Verrill), 1871. [Eugyra pilidaris + Molgula 
pellucida Verrill]. 
Gulf of Saint Lawrence to North Carolina, 
i to 120 fathoms. 
Genus Caesira Fleming, 1822. 
[= Molgula auct. plur.]. 
17. Caesira lutulenta, sp. nov. 
Off the coast of southern New England and the Middle States. 
67 to 142^ fathoms. 
18. Caesira manhaltensis (DeKay), 1843. [Molgula Manhattensis Verrill]. 
Vicinity of Cape Ann, Mass., to North Carolina. 
Shallow water only (near low-water mark, occasionally to 16 fathoms). 
19. Caesira septentrionalis (Traustedt), 1882. 
Northern waters of Europe, and Greenland. One specimen from the 
Banks of Newfoundland. 
Greatest depth 50 fathoms. 
20. Caesira intumescens, sp. nov. 
Two specimens from the Banks of Newfoundland. 
Depth of 39 fathoms recorded for one specimen. 
