307 
Chtamalus moro Pilsbry. 
Zamboanga, from stones on the beach. 25/11 14. Numerous specimens 
together with Tetraclita squamosa, and Tetraclita vitiata. 
The present specimens differ in colour from Pilsbry’s de- 
scription (1916), most of them being lighter or darker brown with 
paler ribs; only some few of them are almost white. — Pilsbry 
only disposed of dried specimens, and I shall, therefore, here give 
some details as to the body of the animal. 
a b 
Fig. 52. Chtamalus moro from Zamboanga. a mandible, 1) maxilla. [X 60]. 
The labrum has an almost straight edge with a single row 
of small spines occupying the middle half; 35 to 40 spines were 
counted in the row. 
The mandible (Fig. 52c) is of the stellatus- type: the fourth 
tooth is small, although double, the comblike part extraordinarily 
short, with only five or six bristles; the three terminal spines are 
all but equal, the median one tending to be the longer one. 
The maxilla has a very little conspicuous notch below the 
upper group of spines; on the other hånd a small, but distinet 
notch is again visible between the stronger spines of the middle 
part of the cutting edge and the lower group of more hairlike 
bristles. 
The anterior c irri are short. In cirrus I the shorter ramus 
measures about 3 A of the longer one, the numbers of the segments 
being 7 and 8. In cirrus II the rami are all but of equal size 
with 6 and 7 segments. Pectinate spines are present in great 
numbers in the two distal segments of both rami of cirrus II, but 
no large-toothed spines are present. In cirrus III—VI the segments 
have three pairs of spines on the anterior side. 
Chtamalus moro is thus characterized by an unusually short 
comblike part of the mandible, and by the numerous pectinate 
20* 
