PACIFIC COAST OLIGOCH MTA. 165 
posed of two distinct lobes of about equal size, one situated closely posterior to the 
other. This is also the structure of the septal glands in iv and y, but the one in vi is 
solid, consisting of only one lobe, when viewed in longitudinal section. The main 
lobes are situated on the same longitudinal muscular band, with their discharge ducts 
running forwards into the pharyngeal cavity. In each of the three somites there are 
two distinct glands on either side of the median line. One larger supraintestinal 
consisting of three parts extending laterally, and one smaller subintestinal. These 
latter ones also open into the pharynx, but into its ventral side, the pharynx 
thus being partially developed even on the ventral side. The discharge tubes and 
chambers are very large, and the latter oceupy more than one-half the width of the 
pharyngeal wall. They stand very close together, and are all of about the same height 
and form (fig. 112). The dorsal wall of the pharynx is much thicker and denser 
than the ventral one, and the discharge chambers stand closer and are of more uni- 
form size, more tubular. The discharge chambers on the ventral side are thicker, 
more pear-shaped and much fewer in number. Fig. 112 represents the lining of 
the dorsal wall of the pharynx; fig. 115 the ventral wall of the same, and fig. 114 
the wall next posterior to the main dorsal section. 
Hsophagus and intestine. The description given by Benham of the histology 
of the intestine of Sp. tamesis may in the main points be applied to this species. 
The cesophagus is cylindrical with parallel sides and slightly nipped by the septa. It 
is sparsely covered by chloragogen cells, which latter are more numerous on the 
intestine. The cilie of the inner epithelium are much longer in the esophagus, 
and so are the epithelial cells themselves. Seen in longitudinal section (fig. 110) 
we find that the transverse muscles surrounding the cesophagus are more numerous and 
present in several rows, while in the intestine they are few and far between, and 
arranged only in one row. There is thus a distant approach to a gizzard in the 
esophagus. The longitudinal muscular layer is reduced everywhere in the intestine 
to a single strand, but in the cesophogus it is double, sending out strands to the septa 
and to the mesenteri¢ sac. 
Blood sinus. Both Benham and Smith have shown the existence of a conti- 
nuous blood sinus in the intestine of the species described by them. Inthe wsophagus 
of our present species we find only a vascular network and confluent smaller lacunes, 
but in the intestine proper we meet with a continuous blood sinus all around the 
epithelial cells. The radiated appearance of the blood in the sinus, as well as in the 
other vessels, must as Benham suggested be due to the erystalization of heematine. In 
Sp. Benhami and Sp. Smithi these crystals are so many and so heavy that they invari- 
ably destroyed the edge of the microtome knife and made sectioning most difficult. 
But the crystalization presents some peculiarities, and in places appears as if there 
was a mass of radiating fibers always from the side nearest the center of the body 
radiating towards the periphery, but never the contrary. In Sp. Benhami these crystals 
are much more slender than in Sp. Smithi. In the latter species their nature is not 
to be doubted. They are also found in the hearts, but more rarely in the main longi- 
tudinal vessels. 
