CONTRIBUTIONS TO THE ANATOMY OF THE HIRUDINEA. 503 



Fig. 25. — Pontobdella. Connective jelly, with corpuscles, a. Elongated 

 corpuscle forming a fibre ; nucleus in some dividing, b. Similar corpuscle, 

 but branched, c. Vacuolated corpuscle. 



Fig. 26. — Pontobdella, Corpuscle containing refringent granules of 

 various sizes, gr. n. Nucleus. 



Fig. 27. — Piscicola. " Fat cells." end. Endoplastic globules, n. Nucleus. 



Fig. 28. — Aulostoma. a. Unmodified connective-tissue corpuscles, b. 



Similar corpuscles, dividing and elongating, d. The corpuscles, as a result of 



division, forming rows, and at e. breaking down to form a lumen, thus ultimately 



giving rise to botryoidal tissue/. 



Fig. 29. — Pontobdella. Very young embryonic corpuscle?, elongating 

 and developing pigment. 



Fig. 30. — Pontobdella. Elastic fibres, fresh, teazed. 

 Fig. 31. — Piscicola. Corpuscles branching and developing pigment, 

 taken from a deep layer. 



Fig. 32. — Piscicola. Similar corpuscles, taken from a more superficial 

 layer. They are more branched, and there are fewer nuclei. 



Fig. 33. — Haemadipsa ceylonica. Mass of branched corpuscles which 

 have fused together. From a superficial layer. 



Fig. 34. — Branchellion. Similar mass from a superficial layer. 

 Fig. 35. — Pontobdella. Corpuscles which have developed pigment but 

 retained their shape. Deep layers. 



Fig. 36. — Pontobdella. Similar corpuscles, showing their arrangement 

 in rows. 



Fig. 37. — Pontobdella. Similar cells, which Lave undergone further 

 division. Median layers. 



Fig. 38. — Pontobdella. Similar cells, which have become much branched. 

 Superficial layers. 



(Figs. 39—43 occur on Plate XXXIII.) 



Fig. 39. — Pontobdella. Blood corpuscles, fresh, n. Nucleus. 



Fig. 40a. — Nephelis. Blood-corpuscles, fresh, n. Nucleus. 



Fig. 40b. — Hirudo. Blood-corpuscles, fresh, n. Nucleus. 



Fig. 40c. — Ditto. Ditto, weak acetic acid. n. Nucleus, 



Fig. 40d. — Ditto. Ditto, magenta, n. Nucleus. 



Fig. 41. — Pontobdella. Coelomic epithelium cells from ventral sinus. 



a. Connective-tissue layer. 

 Fig. 42. — Pontobdella. Similar cells. This is a very complete instance 

 of their occurrence from a transverse section of a branch of the ventral 

 sinus. /. n. The lateral nerve branch, about to divide into a dorsal 

 and ventral branch, cosl. Coelomic space (sinus), a. Connective 

 tissue layer. 

 Fig. 43. — Pontobdella. Similar cells, seen in a flat section lining the 



