272 Martin, A Note on the Occurrence of Nematocysts and Similar Structures etc. 



Oersted. Plattwiirmer. Kopenhagen 1844. 



Du Plessis. Sur le Monotus setosua, n. sp. Zool. Anz., Bd. XII. 1889. 



Saville Kent. A Manual of the Infusoria. London 18801882. 



Schuberg. Uber Cilien und Trichocysten einiger Infusorien. Archiv f. Proti^t.. 



Bd. VI. 1905. 



Siebold, von. Lehrbuch der vergleichenden Anatomic. 1848. 

 Strethill Wright. (1) Proc. Roy. Phys. Soc., Vol. I. 1856. (2) Q. J. M. S., 



Vol. III. 1863. 

 Troschel. Bemerkungen iiber die Cephalopoden von Messina. Arch. f. Naturges., 



23. Jahrg. 1857. 



Text Figures. 



I. (a) Diagram showing proboscidiform individual of Opliryodendron abieUnum 

 with extended proboscis feeding on a tentacle of an Obelia. 4 comp. 

 oc. -f- 4 mm apochr. 



(b) Details of the same preparation; one cell has just been dragged by the 

 tentacle of the Opliryodendron out of its position in the ectoderm. 

 6 comp. oc. -4- 2 mm apochr. 



(c) Later stage in the feeding of an Ophryodendron; the proboscis is now 

 retracted and carries at the end of some of its tentacles ectodermal cells 

 from the Obelia (X 1). 



X 2 an ectodermal cell on its way down the proboscis. 



X 3 ectodermal cells of the hydroid in various stages of digestion. 



6 comp. oc. -(- 2 mm apochr. 



II. Cleptocuidae of Potykrikos (after Butschli, Protozoa, Bronn's Tierreich, 

 PL LV, fig. 8c). 



(a) Nematocysts unexploded. 



(b) Nematocysts exploded. 



III. Pseudocnidae of Epistylis umbellaria, 



(a) unexploded condition, 



(b) exploded condition after addition of dilute acetic and methylene blue. 



IV. Cleptocnidae (V) in Pnrifera (after Eimer, Nesselzellen und Sameu bei See- 

 schwammen. Archiv f. mikr. Anat., Bd. VIII, 1892, p. 283); the full length 

 of the thread shown in the original figure of Nematocyst B is not reproduced 

 here. NB. The original figures in this case are very rough. 



V. Cleptocnidae in Microstomum lineare, 



(a) exploded hydra Nematocyst lying in its vacuole under the skin of Micro- 

 stomum lineare, 



(b) part of a section through a Microstomum showing an unexploded Hydra 

 Nematocyst in the gut and in a vacuole under the skin, 



(c) exploded Cordylophoran Nematocysts lying under the skin in Micro- 

 stomum lineare. 



VI. Pseudocnidae of Nemertinea, 



(a) Pseudocnidae of Cerebratulus urticans in the exploded condition. 4 comp. 

 oc. -4- 4 mm apochr., 



(b) Pseudocnidae Micrura purpurea in an unexploded condition. 6 comp. 

 oc. -4- 2 mm apochr., 



(c) Pseudocnidae Micrura purpurea immediately after explosion showing the 

 thread. NB. The full length of the thread is not shown, 



(d) Pseudocuidae of Micrura purpurea after the disappearance of the thread. 

 VII. Cleptocnidae of Aeolids (after G-rosven or, "On the Nematocysts ofAeolids' 7 , 



Fig. 13, "Transverse Section through middle of a Cnidosac of R. Peref/rina, 



