290 ON TOPOGEAPHICAL RELATIONS AMONG THE DOCOGLOSSA. 



L.K.Ap. = Aperture of post-torsional left kidney, 



L.-M. = Junction of loops L and M of the intestine. 

 L.M.T. = Lesser mantle-tentacle. 

 L.R.P. = Reno-pericardial canal of the left kidney (renal pore). 



M. = Dorsal intestinal loops characteristic for Cyclobranchs. 

 M.-L. = Junction of loops L and M of the intestine. 

 Meso. = Connection between ventricle and dorsal wall of pericardium. 

 Mt. = Mantle-skirt. 

 M.Tent. = Mantle-tentacle. 



iV. = Ventrally-placed loop of intestine following loop M in Patella vulgata^ 

 N.R. V. = Veins from nuchal roof. 

 Oes.P. = Lateral oesophageal pouches. 

 Op. = Operculum. 

 Osph. = Ospbradium. 

 P. = Pericardium. 

 Post. A. = Posterior aorta. 

 Pr. and arrows indicate direction of pressure of viscera on pericardium, 



P.Z. = Pigment-zone. 

 Q (curve) indicates tlie part of region A of the gut which is pushed to the left Ijy pressure from 



the right anterior corner. 

 Qi indicates the part of region A of the gut which is pushed inwards and backwards by pressure from 

 the right anterior corner. 



R. = Rectum. 

 R.Au. = Right auricle. 

 R.Ct.V. = Right efferent ctenidial vein. 



R.K. = Right kidney. 

 R.K.Ap. = Papilla and aperture of post-torsional right kidney. 

 R.R.P. = Reno-pericardial pore of the right kidney. 

 S.M. = Shell-muscle. 

 Sp.C. = Spiral caicum. 

 St. = Slit in mantle. 

 T. = Cephalic tentacle. 

 V. (upper & lower) = Upper and lower parts of the consolidating visceral mass. 

 V.F.G. = Folds which are ventral in the gullet-wall. 

 Vn. = Ventricle. 

 X and 3 arrows indicate pressure obliquely backwards from the right anterior corner of the visCeral 



mass causing curve Q^. 

 Y and 2 arrows indicate pressure inwards from the right side of the visceral hump. 

 Z and 1 ari'ow indicate pressure forwards at the back of the visceral hump. 



