1896.] FROM THE SANDWICH ISLANDS. 199 
constant up to the end of the body. The formula’ will read 
thus :— 
Segment ...... ra VW XII. Vs 
No. of set ...: 23 31 43 46 
but on some seginents quite close to the tail I counted as many as 
49 sete. The size of the setz varies on different segments and on 
different parts of the same segment. The setw on either side of 
the nerye-cord, as is the case with other species (e. g. Pericheta 
houlleti), are larger than those more laterally placed. This 
difference commences to be well marked in the third setigerous 
segment, anterior to which, it may be observed, is no ventral nerve- 
cord, but the circumeesophageal commissures. From the third 
setigerous segment to the sixth (inclusive) there is this marked 
difference between a few ventral sete—particularly the ventral- 
most seta—on either side of the nerve-cord and the rest of the sete 
of the segment. On the tenth segment all the set are very 
much smaller than on the preceding segments”, and those on 
either side of the ventral nerve-cord are not larger. On the 
eleventh segment the sete againare larger, and there is a slight 
difference in size between the ventralmost two or three sets and 
the rest, but not nearly so marked as on segments iv.—vii. 
The clitellum is, as has been already mentioned, entirely witnout 
set ; but no doubt in the immature worm they are present. In 
any case the special longitudinal muscles of the sete were quite 
obvious in the mature worm, At the hinder end of the body the 
sete are larger than those of some of the anterior segments—a 
difference which may have to do with the habit (so general 
among earthworms, at least of this country) of lying outside the 
burrow with the tail only concealed within. 
The first septum lies between segments v./vi. The septum 
between viii./ix. is missing, as is nearly universally the case with 
Pericheta. The septum between ix./x. is largely defective, though 
not absent; it consists chiefly of a strong muscular band on 
each side, which is attached to the insertion of the next following 
septum. Septa v./vill., x./xiil. are moderately thickened. 
In the hinder part of the body were paired masses of coelomie 
cells, attached on either side of the dorsal blood-vessel, such as I 
have described in Perichata. They were full of Gregarines. 
The pharynx is beset with numerous salivary glands, which 
extend back as far as the sixth segment. The gizzard is globular, 
not in any way elongated. 
The last heart is in segment xiii. 
The sperm-sacs are in segments Xi., xii. ; there are, as usual, two 
pairs of sperm-duct funnels. 
* This is a little different from the segments originally selected (‘‘On some 
Species of the Genus Pericheta,” P.Z.S. 1892, p. 157); but as the number 
culminates at xvi. I have thought it well to emphasize the fact by the formula. 
* In relation to this fact, it is interesting to observe that in Pericheta 
caducicheta (Beuham, Ann. & Mag. Nat. Hist. ser. 6, xvi. p. 47, 1895) the seta 
upon this segment are absent. 
