MARINE INFUSORIA. 13 ', 



typified by the genus Acineta, aud distinguished by the possession of 

 tubular tentacle-like appendages, each of which usually terminates in a 

 sucker-like and slightly expanded disc. With those suctonal organs 

 other animalcules are seized, and their protoplasmic contents sucked 

 out and transferred to their own bodies. Many of these Acinetidsa 

 dui-ing a considerable part of their existence lead an endoparasitic life 

 within the body substance of larger Ciliate Infusoria, such as Vorticella 

 and Paramecium, a circumstance which led Stein to infer that tlie 

 AcinetidsB were not independent organisms, but developmental phases 

 of their selected hosts. This hypothesis, however, is now entirely 

 abandoned, and Acineta and its allies recognised as representing an 

 entirely independent, extensive, and highly interesting Protozoic group. 

 Hemiophrya pcmmipara was first described by Dr. Hertwig in the year 

 1875, " Morphologisches Jahrbuch," Band I.,) as a species of Podophrya 

 and has been adopted as the type of an independent genus by myself, 

 (" Manual of the Infusoria," now going to press,) with reference to the 

 peculiar character of the tentacular appendages first pointed out by its 

 discoverer, and frequently confirmed by my own personal observation. 

 These appendages are, in fact, of two sorts, consisting partly of the ordinary 

 tubular and suctorial organs, and partly of non-tubular ones, which are 

 eimply prehensile, thus resembling pseudopodia, and which, extending 

 peripherally to a considerable distance, seize and bring food material 

 within reach of the suckers. The specific name of gemmipara has been 

 conferred by Hertwig on this type with relation to its conspicuous 

 gemmiparous mode of reproduction. Large bud-hke processes, varying 

 from one or two to as many as six or eight in number, are developed at 

 the distal extremity of the body ; within each of these a diverticulum of 

 the branching endoplast or nucleus is produced, and the entire bud or buds 

 are ultimately constricted off and set free in the form of free-swimming 

 cihated embryos. Examples of this interesting type wez'e encountered 

 In the polj'pidoms of Bugula, Crisia, and other Polyzoa obtained from 

 vai-ious depths, and with the aid of osrnic acid specimens were success- 

 fxilly mounted exhibiting the tentacles in a condition of full expansion, 

 as also with the characteristic embryos attached. 



8. — Ophryodendron pediceUatum, Hincks, (Plate TV., Figs. 12 to 14.) — 

 This singular form, figured and described at length by the Eev. Thomas 

 Hincks in the " Quarterly Journal of Microscopical Science " for January, 

 1873, and obtained by him at Ilfracombe, North Devon, was sparingly 

 encountered, and on one occasion only, attached to a species of Plumularia, 

 brought up with the deeper di-edgings. In their normal condition the 

 animalcules of this species are separable into zooids of two denomina- 

 tions. Both are seated on short pedicles, and possess, in the one instance, 

 a simple vermiform contour, with a more attenuated distal termination, 

 and in the other have a cup-shaped basal region or body-mass, from the 

 centre of which is produced an attenuate highly extensile and retractile 

 proboscidiform organ, the apex of the same supporting a fascicle of minute 

 tentacle-like processes, which, when the proboscis is exerted, are 

 maintained in a state of active motion. Among the examples obtained 



