Spengelomenia. 467 
into a comparativly wide chamber whose walls ‘are fashioned into 
the usual ridges enclosing the cirrose area. The inner ridge is 
somewhat obscured by a few adjoining folds that extend into the 
definite pharyngeal tube, but otherwise both it and the outer ridge 
are typical (Pl. 24, Fig. 1). 
The opening from the atrium into the pharynx is comparativly 
wide, and the point of union is marked by the commencement of a 
set of glands that completely surround the digestive tube as far as 
the radula. Definite eircular and longitudinal muscle sheaths like- 
wise appear, and the epithelial lining becomes folded, the appearance 
in cross section bearing a strong resemblance, in this respect, to 
Strophomenia. A pair of strong retractor muscles attach to the 
body wall at the sides of the animal about the level of the 
posterior end of the radula, and on the other hand are inserted in 
the pharynx a short distance in front of the outlets of the ventral 
salivary glands. 
The radula is well developed, is of the monoserial type and, 
jJudging from transverse sections alone, comprises 32 teeth. Each 
tooth (Pl. 25, Fig. 17) consists of a basal section from which, 
without any line of demarcation, two large triangular cusps arise, 
In turn each cusp bears from one to three needle-like processes, 
their form and number differing even on the cusps of the same tooth. 
In the angle between the cusps there is located a small, square or 
vectangular plate, apparently an expansion of the basal division, 
and this likewise bears small spines, somewhat variable in shape 
but invariably three in number. The direction of the sections 
renders it difficult to determine the number and arrangement of 
the odontoblasts, and this same difficulty is again met with in an 
attempt to reconstruct the slender radular muscles and the small 
spherical cells that apparently function as radular supports. 
Up to the level of the radula the salivary glands present the 
form of small lobules, composed of small pyriform cells, closely packed 
together, their ductules opening by intercellular channels into the 
digestive tube. Beyond this point huge groups of pyriform cells, 
fashioned into globular lobules much as in the genus Alexandromenia, 
oceur along the dorsal and lateral surfaces of the pharynx which in 
consequence is displaced far toward the ventral surface of the body. 
Fully a dozen pairs of these lobules are present, most if not, all of 
them apparently in communication with one of the two main, slender 
ducts coursing along the sides of the pharynx (Pl. 24, Fig. 1). In 
