PLATE X. 



Structure of the Eye, &c. 



Fig. 1. Single element of the eye of Serolis cornuta, depigmented by nitric acid ; 

 h, hyaline cell which has absorbed the jjigment. 



Fig. 2. Dissection of Serolis cornuta; h, heart; hep, hepatic cseca ; od, oviduct; 

 r, rectum. 



Fig. 3. Diagrammatic transverse section through the eye of Serolis necBra ; n, nuclei of 

 Semper; /, vitreous body; {g) mass of cells below the vitreous body traversed 

 by a network of pigment. 



Fig. 4. Masticatory stomach of Serolis schytliei ; RP, LP, ribbed lateral plates ; I, la, 

 Ip, lateral ossicles; 1, 2, 3, pyloric ossicles. 



Fig. 5. Diagrammatic transverse section of eye of Serolis hromleyana ; h, vitreous bodies ; 

 c, cornea ; m, tissue in which vitreous bodies are imbedded. 



Fig. 6. Transverse section through the buccal region of Serolis septemcarinata ; a, 

 entrance to the buccal cavity ; m, mandible ; h, buccal cavity ; c, integument 

 bounding the lower surface of the body ; d, salivary glands ; e, connective 

 tissue cells ; n, nerve commissure. 



Fig. 7. Embryo of Serolis anta7vtica ; c, telsou. 



Fig. 8. Single element of the eye of Serolis necera isolated by teasing in glycerin ; v, 

 vitreous body with pigment sheath ; g, mass of cells below the vitreous body. 



Fig. 9. Masticatory stomach of Serolis hromleyana; m, cardiac ossicle; V, ventral ossicle; 

 RP, LP, ribbed lateral plates; I, la, Ip, lateral ossicles; 1, 2, 3, pyloric 

 ossicles ; s, opening of pylorus ; t, triangular ossicle. 



