339 
moreover the equidistant position of the three prominent teeth of 
the mandible as also the broad pectinate part of the lower angle. 
In the maxi 11a a very distinet notch separates the upper two 
large spines from the lower densely spined part of the cutting edge. 
One more difference 
must be noted as contra- 
dictory to Darwin’s de- 
scription. He found that 
both cirrus II and III are 
remarkablyshort,andcount- 
ed 7 segments in both 
rami of cirrus III. The 
specimen dissected of forma 
breviscutum has on the whole more segments in the cirri as shown 
in the following table. 
Fig. 72. Tetraclita purpurascens f. breviscutum 
from Port Ross. a labrum, b mandible, c max- 
illa. [X 25]. 
Cirrus 
I 
II 
III 
IV 
V 
VI 
Numbers of j 
inner ramus 
10 
10 
21 
20 
24 
23 
segments 1 
outer „ 
17 
11 
22 
21 
25 
28 
It will be seen here that cirrus III in numbers of segments 
joins the posterior three cirri, but its size almost equals that of 
cirrus II. In cirrus III the larger spines of the median segments 
of both rami are moreover pectinate, a character not mentioned 
in this species by Darwin, although he has observed the same 
feature in Tetraclita squamosa (= porosa ). 
The penis is annulated all over, and almost destitute of hairs 
except at its distal end, where two small tufts are found at the 
sides of the somewhat bilabiate tip. The penis is a little longer 
than cirrus VI. 
Tetraclita vitiata Darwin. 
Zamboanga; on stones on the beach. 25/11 14. Some young specimens 
together with Tetraclita squamosa, and Chtamalus moro. 
The skeletonal features exaetly agree with Darwin’s description 
(1853); the specimens seem to be somewhat smaller than Dar¬ 
win’s specimens, but this may be due to the faet that the basal 
part is wanting in the present specimens, the sheath in all of them 
almost reaching the lower margin of the pariety. The only differ- 
22 * 
