1370 CHELIDONOPSIS 



moderate ; posterior very faint ; pallial line faint. Valves thin, 

 light, subtransparent, of a very beautiful brilliant olive-green, 

 passing into a grayish-green posteriorly, with very narrow, 

 diverging rays, more distinct towards the margins ; lines of 

 growth fine and irregular, a little stronger towards the ventral 

 margin. Nacre quite iridescent, greenish-blue, sometimes 

 tinged with orange towards the beaks. 



Length 85, of anterior region 30, of posterior region 56, 

 height 30, in front of the beaks 29, at the beaks 24, diam. 14 

 mm." (Germain). 



Type locality, Stanley Pool. 

 Chelidonopsis roubaudi Germain, Bull. Mus. Hist. Nat., 1908, 



p. 160, figs. 31-33; Arch. Zool. Exp. et Gen., (5), I, 1909, 



p. 4, figs. I, 4, 6. 



"The Chelidonopsis ronhandi can only be compared with 

 Chelidonopsis arietina Rochebrune. It can always be easily 

 distinguished by the following characters : 



a. By its more regularly semi-elliptical form, the anterior 

 region being much shorter and very much rounder, although 

 the antero-dorsal angle remains sharp. 



b. The posterior ligament is more developed and propor- 

 tionately stronger. 



c. The anterior region, though presenting the same mode 

 of articulation, has not the two small, diverging" carinse near 

 the dorsal margin, which are present in C. arietina. 



d. In C. arietina the posterior region has two, widely ex- 

 tending, tubular carinas, separated at their extremities, con- 

 stituting, as it were, two wings. The characters of C. rou- 

 baudi are quite different : the carinas are not tubular, they 

 are much less projecting and do not give rise to the wing for- 

 mation so characteristic of the other species. A comparative 

 examination of the figures shows, that C. roubaudi is, evident- 

 ly, a connecting link between the genera Chelidonopsis and 

 Mutelina Bgt., permitting the definite determination of the 

 true affinities of Chelidonopsis, which, by the peculiar charac- 

 ter of the shell, appears widely separated from the other Afri- 

 can groups." 



