286 J- Playfair Mc Murrich, 



proximal part of several well developed brauching and slightly 

 anastomosing- mesogloeal processes, each of wliicli arises independently 

 l'rom tlie column mesogloea, but the distal two-thirds of the muscle 

 is composed of long processes wliich arise from a common, well- 

 developed pedicle, lipon wliich tliey are arranged palmately, those 

 on the distal surface of the pedicle anastomosing to a considerable 

 extent. In section the muscle has what may be termed a semi-oval 

 form. The endoderm of the column wall, disc and tentacles contains 

 a considerable amount of brown pigment in the form of granules. 



The longitudinal muscles of the tentacles and the radial muscles 

 of the disc are moderately developed and are ectodermal in position. 

 The stomatodaeum is longitudinally ridged and, in two of the 

 three individuals of which detailed examination was made, it possessed 

 but a Single deep siphonoglyph. 



The mesenteries in all three individuals examined showed 

 departures from a purely hexamerons arrangement. In one individual 

 there were two pairs of directives, between which there were on 

 one side of the body twelve pairs of perfect mesenteries and 

 on the other side twelve pairs also plus an additional Single 

 perfect mesentery situated next one of the directives. In a second 

 individual, slightly larger than the first, there were twenty-nine 

 pairs of perfect mesenteries, including the Single pair of directives, 

 and in addition there were a few scattered pairs of imperfect 

 mesenteries which lacked muscle pennons. In the third and largest 

 individual there were in what was approximately one-half of the 

 circumference twenty-seven pairs of perfect mesenteries, together 

 with a few scattered imperfect pairs, one of these latter, however, 

 possessing a distinct though weak muscle pennon. There was but 

 a Single pair of directives. In sections passing below the level of 

 the stomatodaeum some of the perfect mesenteries appeared broader 

 than the others and it was possible to recognized in this way three 

 series; in the half of the circumference sectioned there were six 

 pairs that were broader than the rest, eight pairs of an intermediate 

 width, the space on either side of the directives containing two 

 pairs of this cycle, and thirteen narrower pairs, one of these pairs 

 being lacking in one of the Spaces next the directives. 



The longitudinal muscles of the perfect mesenteries form moder- 

 ately developed pennons, broad but not high. The parieto-basilars 

 form a well marked fold which extends upward almost to the disc 

 and the basilar muscles are well developed, having the form shown 



