THE ANATOMY OF PBNTASTOMUM TERETIUSOULUM. 67 



which base of hook lies. Hk. M. Hook muscles, Hk. n. Hook nerve. L. M. 

 Limiting membrane of sense-organ. M^. Muscles in oral papilla. M^. Muscles 

 from side of pharynx to ingrowth of cuticle around oral papilla. M.j. Muscle 

 band inserted into posterior angle of mouth. M. Gl. Modified stigmatic glands 

 near mouth. M. long. Longitudinal muscles. M. Tr. Circular muscles. 

 M. V. S. Muscles in wall of vesicula seminalis. 0. P. Upper lip or oral 

 papilla. Fa. 01. Parietal glands. Pe^ and Pe^. Modifications of epithelium 

 in posterior wall of pharynx. ^S". 0. Sense-organ. St. Gl. Stigmatic glands. 

 To. Tooth-like structure in posterior wall of pharynx. T. P. Membrana 

 propria in wall of vesicula seminalis. V. S. E. Glandular epithelium of 

 vesicula seminalis walls. 



Fig. 32. — Longitudinal vertical section through the mouth region of a large 

 mature female form. The oral papilla with its special muscles is cut through, 

 and also the muscles {M^.) running forwards from the pharyngeal walls. In 

 the ventral wall of the pharynx is the tooth -like structure {To.") which runs 

 upwards, and is connected with a swollen pad composed of an outer and inner 

 layer. Special muscles are connected with the posterior wall of the pharynx, 

 and one band of fibres {M^.) is inserted into the cuticle just at the angle of the 

 mouth. Close to the mouth lies a special group of modified stigmatic cells. 



Fig. 33. — Section through the basal part of a hook, and the invagination in 

 which it is placed. Through the centre of the basal part and between the 

 muscles runs a nerve (5) which is continuous with a swollen spindle-shaped 

 mass composed of fibres and nuclei. This breaks up distally, and its fibres 

 are connected with the subcuticular cells in the base of the hook. Zeiss, apo., 

 4'0 mm., 0'95 apert., oc. 4. 



Fig. 34. — Sense-organ on one of the secondary papillae on the head region. 

 The whole is made of elongate cells in which no nuclei can be seen, and which 

 are directly continuous at their internal ends with a small nerve. A fine 

 limiting membrane appears to invest the organ. Zeiss, apo., 4"0 mm., 0*95 

 apert., oc. 12. 



Fig. 35. — Semi-diagrammatic representation of the nerve-ganglion mass 

 seen from above. The drawing represents the result of examination of dis- 

 sections, and of continuous series of sections. The different nerves given off 

 are numbered, and their distribution is described in the text under these 

 numbers. 



Fig. 36. — Semi- diagrammatic representation of the nerve-ganglion mass 

 seen from the side. Numbers as in Fig. 35. 



Fig. 37. — Section across the wall of the common portion of the vesiculae 

 seminales close to the testis. Externally lies connective tissue and muscle- 

 fibres, and within these lies a layer of columnar cells, the outlines of which 

 cannot be clearly detected. Many of them have their inner ends much swollen 

 out and vacuolate, and contain the coagulated remains of a fluid secretion. 

 Zeiss, apo., 4'0 mm., 0'95 apert., oc. 4. 



