GENUS OPHRYODENDRON. 851 



to the fanciful resemblance of the extended proboscis with its terminal tuft of cirri 

 to a miniature fir or larch. These cirri, in the form now under consideration, are 

 longest at the basal part, becoming gradually shorter as the apex is approached, and 

 in the living state are in a condition of constant agitation, as though seeking for 

 appropriate food. The proboscis becomes transversely annulate in its semi- or com- 

 pletely retracted state, and is extended or withdrawn with remarkable rapidity. 



The navicula-shaped bodies observed by Claparede and Lachmann in examples 

 of this species, and regarded by them as " trichocysts," are apparently of an adventi- 

 tious nature, not being equally constant in individuals derived from the same locality, 

 and are altogether absent in the specimens from the Welsh coast examined by 

 Mr. Hincks. In consequence of the dark granular nature of the parenchyma, these 

 same authorities, while suspecting the existence of an endoplast and contractile vesicle, 

 were not able absolutely to determine its presence. 



Prof. C. Robin, in a recent reference to Ophryodendron abietinum* expresses the 

 opinion that the vermiform zooid is a parasitically attached worm-larva, and describes 

 it as being affixed to its host through the medium of a slender chitinous rod, one end 

 of which is imbedded in its own body-substance, while the other penetrates the cuticle 

 of its host, and is armed, see PL XL VI 1 1 A. Fig. 32, with four or five booklets which 

 serve to anchor it in its attached position. The intermediate phases which have 

 been observed by Fraipont, Claparede and Lachmann, and other authorities do not 

 appear to have fallen within the notice of this investigator. 



Ophryodendron sertulariae, Str. Wright sp. PL. XLVIII. FIGS. 38-40. 



Body of primary or proboscidiform zooids subcircular or elliptical, 

 sessilely attached, very much depressed or flattened ; the proboscis 

 flattened, transversely rugose, developed eccentrically in close proximity to 

 the lateral periphery ; terminal cirri of the proboscis varying from about 

 twenty to forty or fifty in number; vermiform zooids elongate, attached 

 without the medium of a distinct pedicle to the body of the primary zooids, 

 or to some foreign object; a branching endoplast and one or more 

 contractile vesicles discernible in the more transparent proboscidiform 

 zooids. Diameter of bodies of primary zooids 1-300"; length of vermiform 

 animalcules 1-200". HAB. Salt water, on Sertularia pumila. 



This species, which is synonymous with the Corethra sertularia of Dr. Strethill 

 Wright, has been regarded by many authorities as identical with the Ophryodmdron 

 abietinum of Claparede and Lachmann. That the two are distinct from each other has, 

 however, been anticipated by Koch and Fraipont, and that such opinion is correct, the 

 author, through a personal acquaintance with Strethill Wright's type, is in a position 

 to substantiate. So recently as August and September 1881, this form has been 

 obtained by him in great numbers, attached to the polyparies of the zoophyte on 

 which it was originally discovered, growing on Fuci collected in the Menai Straits, 

 North Wales, Acineta tuberosa and A. livadiana being abundantly represented in its 

 vicinity. The most conspicuous features, by which it may be readily distinguished 

 from the forms which it most nearly resembles, viz. O. abietinum and O. porcellanum, 

 . consist of the remarkably depressed contour of the body of the primary zooids and 

 the essentially eccentric or peripheral development of the proboscis. This last-named 

 feature, though indicated in Strethill Wright's original drawings, has not so far been 

 specially mentioned by any writer. In some of the more transparent specimens 

 preserved with osmic acid, a band-like, variously branching endoplast or nucleus, 

 and one or more contractile vacuoles were distinctly visible. The proboscis, under 



* 'Journal of Anatomy and Physiology,' 1879; also 'Journal of the Royal Microscopica 

 Society,' October 1880. 



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