516 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
Station 364 (off Cape Cod, N. lat. 41° 58^', W. long. 69° 44', 70 fathoms, 
hard sand and broken shells). 
Station 371 (16 miles off Chatham, Mass., N. lat. 41° 35|', W. long. 69° 35', 
34 J fathoms, coarse sand). 
Caesira verrilli, sp. nov. 
PI. 53, fig. 53-57; text-fig. 20. 
The only specimen in the collection is of rather regular form, 
measuring about 9 mm. long, 7 mm. deep, and 5.5 mm. transversely 
across the body. The siphons, which are drawn in almost even with 
the surface of the body, arise rather near together on the anterior 
part of the dorsal surface. The atrial siphon has the orifice distinctly 
Text-fig. 20. — - Caesira verrilli, sp. nov. X 4. 
f our-lobed ; the lobes of the branchial siphon cannot readily be counted 
in its strongly contracted condition. Test of moderate and even 
thickness; it would be somewhat transparent were it not quite thickly 
and evenly covered with foraminifera, sand grains, etc. 
Musculature of the mantle rather weak and composed entirely of 
very slender muscle fibers. These bands are quite regularly arranged 
on most parts of the body, forming a network of transverse and longi- 
tudinal fibers with rather small square or somewhat wedge-shaped 
meshes. ^ One set of bands arises in a radiating manner from about 
the bases of the siphons and reaches quite to, in some cases apparently 
across, the mid-ventral line. 
Tentacles of at least four orders, placed quite regularly according 
to the usual scheme of arrangement. They are provided with the 
broad membranes attached along the stem and branches that are usual 
in this group. The largest tentacles number about eight and are 
bipinnately branched, as are also those of the second order. The 
