680 R. C. PUNNETT. 
PLATE XLV. 
Fic. 42. Pt. flava, var. gracilis. Section through hinder part of collar region. «x 45. 
Fie, 43. Pt. flava, var. laccadivensis. Sections through stomochord. All x 85. 
a. Near anterior extremity. 
b, At anterior level of lateral diverticula. 
c. Through lateral diverticula at their maximum breadth. 
d. In region of nuchal skeleton. 
Fie. 44. Pt. flava, var. gracilis. Through stomochord, shewing completely obliterated lumen. x 85. 
Fic. 45. Pt. flava, var. cooperi. Through keel of nuchal skeleton. x 85. 
Fie. 46. Pt. flava, var. cooperi. Through proboscis stalk close to opening of proboscis pores. x 85. 
Fic. 47. Pt. flava, var. cooperi. Through post-branchial groove. The groove is large and the 
genital pleurae well marked. «x 45. 
PLATE XLVI. 
Sections through the region of the branchial and post-branchial groove in several species and 
varieties of Ptychodera. All x 27. 
Fic. 48. Pt. flava, var. parva. Through middle of branchial region. 
Fic. 49. Pt. flava, var. laccadivensis. Through post-branchial groove. 
Fic. 50. Pt. flava, var. gracilis (Hulule). Through middle of branchial region. 
Fie. 51. Pt. flava, var. laccadivensis. Through hind end of post-branchial groove. 
Fic. 52. Pt. asymmetrica. Through middle of branchial region. 
Fie. 53. Pt. flava, var. gracilis (Hulule). Through hind end of post-branchial groove. 
Fie. 54. Pt. flava, var. gracilis (Minikoi). Through branchial region. 
Fig. 55. Pt. flava, var. gracilis (Minikoi). Through hind end of post-branchial groove. 
Fig. 56. Pt. asymmetrica. Through posterior branchial region. 
Fie, 57. Pt. flava, var. laccadivensis. Through middle of branchial region. 
Fie. 58. Pt. asymmetrica. Through hind end of post-branchial groove. 
