GENUS HEMIOPHRYA. 



823 



embryos, as obtains in the genus PodopJvya. The nucleus or endoplast has a 

 tendency Ukewise to become branched or complex, sending out diverticula into 

 the substance of the anteriorly produced gemmules, instead of being simply ovate 

 as in the last-named genus. A third more subordinate but at the same time note- 

 worthy distinctive feature, pointed out by Maupas, is afforded by the mode of 

 union between the animalcule's body and its supporting pedicle. In Podophrya no 

 abnormal feature is discernible, but in Hemiophrya it mostly happens that the 

 pedicle seems to be continued into the substance of the body, such appearance 

 being due to the fact that the body is hollow or invaginated at this point, and thus 

 overlaps the adjoining regions of the pedicle. 



Hemiophrya gemmipara, Hertwig. 

 Pl. XLVI. Figs. 48-51 and Pl. XLVII. Figs. 9-14. 



Body contractile and somewhat variable in form, usually cup-shaped or 

 subpyriform, widest anteriorly and tapering gradually towards its point of 

 junction with the pedicle; tentacles protruded in a crown-like mannerfromthe 

 entire anterior border ; those of a suctorial character subcentrally developed, 

 short, usually five or six in number ; the prehensile tentacles three or four 

 times as numerous, their length when extended exceeding the diameter of 

 the body, their external surface granulate in a spiral direction ; pedicle about 

 four times the length of the body, most slender at its point of attachment, 

 and gradually increasing in diameter towards its distal extremity, hollow 

 interiorly, its external surface both transversely and longitudinally striate ; 

 contractile vesicles two or more in number, situated towards the anterior 

 border ; endoplast usually scimitar-shaped, subsequently more or less rami- 

 fied ; multiplying by the production of gemmules from the anterior border, 

 which are liberated in the form of oval embryos clothed with cilia on one side 

 of the body only, after the manner of the Hypotrichous Ciliata ; parenchyma 

 transparent or enclosing reddish-brown granular matter. Length of body 

 1-400" to 1-125". Hab. — Salt water. 



This animalcule, which is figured and described at length by Dr. R. Hertwig, in 

 the ' Morphologisches Jahrbuch,' Band i., 1875, under the title of Podophrya 

 gemmipara, yields many points of interest. In its possession of certain tentacles, which 

 are not suctorial, but simply prehensile, it may be regarded as a transitional form 

 between the families of the Acinetidse and Ephelotidas, while the released embryos 

 in their hypotrichous form of ciliation correspond closely with those of Acineta 

 cucidlus and Dendrocometes paradoxus. Of these ciliate embryos, it not unfrequently 

 happens that as many as six or eight are clustered upon the anterior border, and 

 into each one of these there divaricates a prolongation of the parent nucleus, which 

 is constricted off and retained within the body of the embryo prior to its hberation 

 into the surrounding water. The supplementary or simply prehensile tentacles of 

 this species present, in addition to their non-possession of suctorial terminations, a 

 marked distinction, as seen under high magnification, from the more characteristic 

 ones of their class. The boundary walls of these appendages, instead of being 

 smooth and even, are more or less coarsely nodular, the component particles of 

 externally developed granular protoplasm being usually disposed in a spiral manner 

 around the central axis. These prehensile tentacular appendages would seem to 

 correspond to some extent with the non-suctorial and muricate tentacula of Acthw- 

 cyathus cidaris. In this respect the structure of the prehensile tentacles is shown to 

 correspond essentially with that of the ordinary suctorial appendages of such a type 

 as Podophrya elongata^ in which, as recently observed by the author, a very distinct 



