134 CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



EXPLANATION OF PLATE XV. 



All drawings made at the level of the microscope stage, with the aid of 

 camera lucida. 



Fig. I. The dorsal nervous system of Epidella squamula, sp. nov. The 

 two main longitudinal nerves are represented, together with their 

 commissures and numerous branches, which form a loose anas- 

 tomosis. 

 The ventral nervous system, showing two pairs of longitudinal 

 nerves, their commissures, and branches. The chief nerves of 

 the posterior sucker are also shown. 

 One of the two reservoirs of the excretory system in a distended 

 and collapsed condition; e, external opening. From same indi- 

 vidual. 

 Transverse and longitudinal sections of two of the cells located 



within the terminal third of the vas deferens. 

 Somewhat detailed drawing of the brain; a, anterior sucking discs; 

 b, brain; c, semicircular commissure; </, dorsal nerves; 0. v., 

 outer, and i. v., inner ventral nerve cords; ph., pharynx. 



Fig. 6. One of the pharyngeal gland cells, showing nucleus [nu.), the 

 secreting portion {g.), numerous intracellular ducts {ca.), the 

 reservoir [re.), and outer opening. 



Fig. 7. Two of the four groups of cells lying directly behind the testes (/.). 



Fig. 8. One of the ganglion cells lying beneath the subcuticular muscle 

 bands. The inner longitudinal nerve is about one-fifth its correct 

 diameter. 



Fig. 9. The posterior sucker, showing the three pairs of hooks and some of 

 the chief muscles which operate them. 



Fig. 10. The eggs of E. squanmla, showing the centrally placed ovum 

 surrounded by yolk-cells. 



