VAN NAME: SIMPLE ASCIDIANS. 
473 
often of such size and attached in such abundance as completely to 
disguise the form and appearance of the animal. Occasionally speci- 
mens have a fairly smooth even coating of sand grains. In living 
specimens the test has a pale greenish yellow or olive color. "The 
branchial orifice is sometimes surrounded within by a ring of dull 
reddish brown, the 6 lobes have each a spot of dark brown with smaller 
ones between. The anal orifice is greenish yellow " (Verrill, 1871a, 
p. 55). The mantle, when the test is removed, is greenish, the in- 
testine and gonads showing through it. 
Text-flg. 4. — Caesira manhattensis (DeKay). X 1-7. 
Large specimens measure 20 mm. to 25 mm. in antero-posterior 
or dorso-ventral diameter, the lateral diameter being somewhat less. 
Mantle musculature rather weak. Muscle bands radiating from 
siphons not very numerous. Over most of the body the musculature 
consists of rather weak and not very closely placed bands of different 
sizes. They cross each other in various directions, the greater num- 
ber having a transverse or somewhat oblique direction. 
Branched tentacles of about four orders are present in addition to a 
variable, but often considerable, number of minute simple or rudi- 
mentary ones. The larger tentacles are arranged with some approxi- 
mation to regularity and numbered in several specimens studied about 
four of the first, four of the second, and eight of the third order, but 
there is much individual variation. Largest tentacles three times 
compound; ultimate branchlets borne numerously on the trunk and 
larger branches as well as on the smaller ones; their tips not at all 
swollen. 
