PACIFIC COAST OLIGOCH MTA. 157 
INTERIOR CHARACTERS. 
_ Septa. Thickest septum is found between somites xi/xii. Anterior septa are 
gradually diminishing in thickness forward, and similarly the septa posterior to xi/xii 
are diminishing in thickness backwards. The most posterior thickened septum, the 
one between xiv/xv, is hardly thicker than the one next posterior. The central 
part of the thickened septa is very much thicker than the part near the body-wall. 
(fig. 127t.m.) The septa correspond more to the intersegmental grooves than do those 
in Sp. Benhami. When the body is viewed in cross-section it will be seen that the 
septa are principally attached to the body-wall at four points nearly half way between 
the sete (fig. 131). 
Suprapharyngeal and septal glands. There are dorsal septal glands in iy, vy, 
vi, vil, about equal in size, and ventral septal glands in y, vi, vil, also of about equal 
size. ‘The latter are much larger than in Sparganophilus Benhami, and reach above 
the center of the body (fig. 120). In addition to these glands I find an accessory 
septal gland attached to the central anterior surface of septum 1x/x, just above the 
intestine and extending downwards. This gland is closely attached at every point to 
the septum, and projects only slightly into the ecelomie cavity. In height this gland is 
not much thicker than the central part of the septum (fig. 152). Its free surface is very 
smooth and even. I could follow ducts with precipitated secretions running along the 
septum downwards towards the intestine, but its connection with the latter, if any, I 
could not ascertain. Beddard suggests that as the nephridia only commence in the 
thirteenth segments the septal glands described by Benham in Sp. tamesis are homo- 
logous with the nephridia. In all species of Sparganophilus investigated by me I find 
no such mucous glands as in Pontoscolex, only regular salivary glands, which open 
into the pharynx, and of the same structure as the supra-pharyngeal glands generally. 
These salivary glands in Sp. tamesis occur exactly in the same somites as in all other 
Sparganophilus species, viz.: iv, y and vi. 
Body-wall offers no other characteristics, except that it is throughout of almost 
the same thickness, and not thinner along the dorsal parts of some of the central 
somites, as in Sp. Benhami. 
Chtellum is continuous all around the body, but it is much thicker dorsally 
than ventrally. This thicker dorsal portion commences with the tubercula pubertatis, 
gradually increasing in thickness dorsally towards the median line, where it is four 
‘times thicker than at the ventral median line between the tubercula pubertatis. This 
refers only to the clitellar cells in the central clitellar somites. The long clitellar 
cells are confined to the latero-dorsal part, while the ventral part contains only 
the short clitellar cells, the point where the former cease being the tubercula 
pubertatis. This is the case in all the species examined by me. 
Tubercula pubertatis. It has already been stated that they form a continuous 
ridge, only broken in the anterior two somites xvii and xviii. Their structure differs 
considerably from that of Sparganophilus Benhami. We find the tubercle cells less 
differentiated (fig. 138), and more resembling the short clitellar cells, of which they 
are only a variety. Another characteristic is the presence of a large blood vessel in 
