On Furcellaria fastigiata and Polyides rotundus. 87 



and of a flesh colour. It is laterally compressed in its upper 

 third, and becomes quite flat where it joins the neck (fig. 2 c) ; 

 its lower two-thirds are rotund (fig. 2d) : it terminates inferiorly 

 by a little process which projects in front and beyond the attach- 

 ment of the ovarian tubes (fig. 3 e) . Viewed on its side, it forms 

 a long narrow ellipsis (fig. 3d). 



The ovaries are an inch and four lines long ; cylindrical and 

 uniform in size throughout their entire length. Their colour is 

 the brightest emerald-green. The ovaries are a little constricted 

 at their attachment to the body, which itself bulges out, and at 

 the junction there is a small scale, which overlaps the point of 

 union (fig. 4) . When the animal was quite fresh, there were in- 

 dications of several articulations or divisions along the ovarian 

 tubes ; but these, as well as their very brilliant colour, have been 

 lost by immersion in spirit. Magnified about twenty diameters, 

 small tubercles are seen on the surface of the ovarian cylinders, 

 especially near their extremities (fig. 5). 



Hub. Attached to the cornea of the eye of a herring {Clupea 

 harengus) from the Devonshii'e coast, near Teignmouth. 



Poole, Dorsetshire, May 25, 1850. 



EXPLANATION OF PLATE VIL B. 



Lerneonema Bairdii. 



Fig. 1. Natural length. 



Fiff. 2. Enlarged about two diameters, and viewed from behind : a, the 

 hook ; b, neck ; c, compressed part of body ; d, rotund part of 

 body ; /, /, ovaries. 



Fig. 3. Lateral \iew : a, b, c, d,f, as above; e, depending process from 

 body. 



Fig. 4. The extremity of the body, showing the attachment of the ovaries 

 (magnified 20 diameters). 



Fig. 5. Extremity of ovary, showing small tubercles on its surface (mag- 

 nified about 20 diameters). 



IX. — Observations on Furcellaria fastigiata, Huds., and Polyides 

 rotundus, Gmel. By Dr. Robert Caspary. 



[With three Plates.] 



As Harvey, in his ' Manual of the British Marine Algae* of 1849, 

 still observes, p. 146, that Furcellai'ia fastigiata, Huds., and 

 Polyides rotundus, Gmel., " can scarcely be distinguished, when 

 out of fruit, except by the root and the rounded axils of the 

 branches,^* it is by no means idle work to show, by an accurate 

 examination of the internal structure of these two plants, that in 

 reality there exist characteristic difl"erences in the formation of 

 their cells, and that those difierences are so striking, that every 



