170 Prof. M‘Intosh’s Notes from the 
the bases of the bristle-bundles in the anterior region, and 
consist of minute, thin, translucent organs, which have a 
long anterior face ending inferiorly in a slightly curved 
spine corresponding to the main fang in other forms. The 
edge appears to be minutely serrated. The outline below 
the main fang forms a narrow gulf, and then trends to 
the thin basal plate. The posterior outline dips imward so 
as to make a prominent and bluntly conical crown, and 
then joins the basal plate. The great number, transparency, 
and delicate nature of these hooks are characteristic 
features. If Wollebcek’s figure* of the look of Protula 
arctica, Hansen, is correct, it differs from the foregoing in 
general shape, shortness of the main fang, large size, and 
small number of teeth above it—indeed, there are five times 
the number in the British form. 
The posterior hooks are smaller, but do not structurally 
differ from the anterior. They are situated on prominent 
lamelle along the sides of the body, and toward the tail 
these are very closely arranged. The very minute serrations 
on the anterior face of these hooks is in contrast with the 
condition in Protula intestinum, and even with De St. 
Joseph’s figure of P. tubularia. 
No form in the whole range of the Polychets is of greater 
interest than the second species, viz., Pilograna implexa, 
Berkeley, the life-history and reproduction of which, its 
plastic and protean character, as well as the concrete cal- 
careous masses, often of considerable size, formed by its 
thread-like tubes, combine to surround it with a halo of 
interest, were it only for the study of variability in a single 
type. In this form the cephalic region presents a smooth 
gap between the rounded ends of the lamella forming a 
border to the anterior division of the body. A little below 
the edge of the lamella on each side is a flattened process of 
the collar which expands considerably distally so as to form a 
conspicuous structure. Ventrally the collar in the prepara- 
tions folds backward as a broad lamella, split distally into 
two lobes, which in all probability are directed forward when 
in the tube. Two eyes occur in the dorsum of the peri- 
stomial segment. Each consists of pigmented spherules 
(“ crystallins,” De S¢. Joseph), numbering in the one seven 
and in the other eye ten. 
The branchiz are eight in number, four on each side, and 
in the spirit- preparations are about half the length of the 
* Skrift. svensk. Krist. 2 Bd. no. 18, p. 120, pl. xlviii. figs. 6a & 60. 
ee 
