380 
PACIFIC SCIENCE, VoL V, October, 1951 
lisabella as a polychaete are the supposed ab- 
sence of setae (which may, however, be rep- 
resented by the chitinized platelets) ; the 
absence of a dorsal groove (which is present 
if the collar is ventral); and the scarcity of 
dissepiments (though this scarcity is known 
for some other annelids). Strong evidence for 
Uschakow’s view is the high palmate mem- 
brane of the crown, the body form, the well- 
developed thoracic collar, the posterior anus, 
the segmentally arranged parapodial-like 
structure, and the uncinial-like structures. 
The subfamily Fabricinae Rioja, 1917, in- 
cludes more than 60 species in 12 or more 
genera. Unlike members of the Sabellinae, 
which are often very large and conspicuously 
colored, the Fabricinae are usually minute 
(only a few millimeters long), but some of the 
Chone group, such as Megachone aurantiaca 
Johnson, are large (more than 80 millimeters 
long). 
The Fabricinae axe remarkable for their 
adaptability to varying intertidal conditions 
and their adjustment to either brackish or 
fresh water. The term ' 'sedentary” is not al- 
together appropriate since many species con- 
struct transitory tubes that are rebuilt after 
removal. Locomotion is forward or backward. 
The most nearly related species in such genera 
as Fabricia and Manayunkia may have inter- 
rupted distributions in widely scattered fresh- 
water regions and intertidal zones (see below). 
In their morphological characters the 
Fabricinae are sometimes separable only 
microscopically from some smaller members 
of the Sabellinae. The most reliable and 
practical character concerns the structure 
of thoracic neuropodial hooks: in the 
Fabricinae they are long-handled (Fig. 3) ; in 
the Sabellinae they are avicular, lacking a 
handle. In the first, the nephridial apertures 
may open only at the anterior end of the 
thorax, mid-dorsally near the peristomium 
(hence the name Thoracogoneata Zenke- 
witsch, 1925); in the second, the nephridial 
apertures are present in thorax and abdomen 
(theAbdominogoneataofZenkewitsch, 1925). 
In the Fabricinae, the muscular tissue is nema- 
toid (Johansson, 1927); in the Sabellinae it is 
not nematoid. In the first there are pulsating 
pouches (Fig. 1), sometimes called branchial 
hearts, in the peristomium; in the second such 
pouches are lacking. 
The Fabricinae are recognizable for 12 
genera including one (Monroika) newly pro- 
posed for an aberrant fresh-water species 
from the Congo River, Africa (see below). 
There are other described species, such as 
Haplobranchus halticus Karling, 1933, from 
Finland, and Fabricia alata Ehlers, 1897, from 
Patagonia, that are not clearly referrable to 
known genera. These 12 genera, with their 
Pacific representatives, are as follows: 
1. Caobangia Giard, 1893, is known for a 
single small species, C. billeti Giard, 1893, 
from Tonkin, French Indo-China, in 
fresh water. See Monro (1939: 232) for 
review. 
2. Chone Kroyer, 1856, is known for about 20 
species, all marine, with the following 6 
from the Pacific: 
C. cincta Zachs (1933: 135) from the 
north Japan Sea. 
C ecaudata (Moore), 1923, from Cali- 
fornia. See Hartman (1942: 135-136, 
figs. e-g). 
C. gracilis Moore (I906: 257-259, figs. 
62-66), from Alaska. 
C infundibuliformis Kroyer, 1856, from 
Arctic and boreal seas of both hemi- 
spheres. See Fauvel (1927: 334-335, 
fig. 116). 
C minuta Hartman (1944: 280-281, figs. 
50-52, 59-60), from California. 
C. mollis (Bush), 1904, from California. 
See Hartman (1944: 279-280, figs. 
47-49). 
Nine of the remaining species are 
known from northern and western Eur- 
ope, two are from the tropical east At- 
lantic, two are from the Arctic Ocean, 
one is from northeast America, and one 
is from South Africa. 
