DR. T. S. COBBOLD ON ENTOZOA. 171 



teen to each circle; the hooks of the two lowermost rows being very large. Magnified 20 

 diameters. 



Fig. 43. Diagram of one of the circlets showing the arrangement of the lesser hooks. Magnified 60 

 diameters. 



Fig. 44. One of the large hooks, to show the blunt extremity directed diagonally outwards and down- 

 wards. Magnified 260 diameters. 



Fig. 45. A small hook, showing its sharp and curved tip pointed vertically downwards. Magnified 260 

 diameters. 



Fig. 46. Head, viewed from above, to illustrate the form and aspect of the two lateral bipartite suckers 

 and the position of the closed orifices of the proboscideal sheaths. Enlarged 8 diameters. 



Fig. 47. Echinostomum hispidum. Natural size. 



Fig. 48. The same, enlarged 15 diameters. It exhibits the uterine tube, testes, ventral sucker and inte- 

 gumentary spines. 



Tab. XXXIII. 



Fig. 49. Another view of the head, showing the oral sucker. 



Fig. 50. Cutaneous spines. The uppermost one is from the neck ; the central, from the first row sur- 

 roimding the head ; the lowermost, from the second cephalic circle of spines. Magnified 200 

 diameters. 



Fig. 51. Dac/mitis spharocephala. Natural size. 



Fig. 52. Distoma clavigerum. Natural size. 



Fig. 53. The same, enlarged 12 diameters. 



Fig. 54. Section of the intestinal tube of the speckled Salamander, laid open to exhibit the mode of attach- 

 ment of Echinorhynchus anthuris to the mucous surface. Natural size. 



Fig. 55. One of the males, enlarged 8 diameters. 



Fig. 56. Caudal extremity of a female, showing the artificially distended and transparent integument, the 

 muscular sac enclosing the reproductive organs, the central oviduct, and certain peculiar acces- 

 sory glands. Magnified 200 diameters. 



Fig. 57. One of the loose globular ovaries containing ova in their nascent condition. 



Fig. 58. Another ovary more advanced. 



Fig. 59. A series of ova isolated from the above to exhibit their different stages of development. 



Fig. 60. Fully developed ovum enclosed in a cyst. 



Fig. 61. Front view of the same. 



Fig. 62. Ovum detached from its enveloping cyst, showing the lateral position of the yelk and the pecu- 

 liar Trichina-like form of the membrane enclosing the albumen. The last six figures are severally 

 magnified 350 diameters. 



Fig. 63. Teenia sphterophora. Natural size. 



Fig. 64. Head of the same. Magnified 200 diameters. 



Fig. 65. Section from three of the segments showing the external reproductive organs and imperfectly 

 developed ova. Magnified 200 diameters. 



Fig. 66. Proscolex removed from one of the caudal segments. 



Fig. 67. Another still more advanced, showing the inverted rostellum with its three pairs of hooks. 

 Magnified 500 diameters. 



Fig. 68. Echinostomum spinulosum. Natural size. 



Fig. 69. The same, enlarged 10 diameters. 



Fig. 70. Posterior view of the head, showing the fin-like disposition of the cephalic spines. 



Fig. 71. Diagram illustrating the arrangement of the vitelline caeca. 



Fig. 72. Ovum. Magnified 300 diameters. 

 VOL. xxn. 2 A 



