KUNGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 59. NIO 3. 55 



tion as in Ch. jukesi. The outer sacs also agree entirely with those of the latter 

 species. There were no traces of foot retractors perceptible among the nephridial 

 lobes. 



The pericard is wide above, narrowing towards the base, till finally it is 

 retained only as the lateral corners from which the pericardial tubes of the nepridia 

 issue. 



The genital organs are composed of tubes with numerous branches which ex- 

 pand all round the body in a single layer outside the liver. They debouch through 

 fissure-like openings with somewhat thickened lips which are situated opposite and 

 somewhat above the nephroprocts. 



In the structure of the gills we have to observe the existence of direct inter- 

 marginal connections between the marginal and the axial veins (ef. Echinochama). 



Chama gryphoides Linné. 



Figs. 66—69. 



Two specimens, one of which was sectioned, originating from Rovigno, Adri- 

 atic, have been examined. 



External morphology (figs. 66—68). 



The mantle is thickened in the left umbo, otherwise rather thin. In the lower 

 margin the openings are pigmented and papillated, as shown in the figures given 

 by Poli (1791, pl. XXIII, fig. 4, fig. 20). The pedal opening is strikingly long, 

 as is fully shown in Poli's figures copied here. 



The adduetor muscles are about equal in size (in one specimen the posterior 

 adduetor is broader, in the other the reverse). 



The labial palps are inserted at equal heights on both sides, immediately 

 above the adduetor; they attain about Vs of its length. 



The gills are coarsely folded, in the anterior gill the folds lie 2 and 2 together, 

 separated by broader furrows (about 17 — 20 double folds can be counted). The 

 posterior gill is considerably narrower than the anterior one and the posterior ad- 

 duetor. In both specimens the gills were separated from each other, but in the 

 smallest one both pairs had coalesced with the mantle; in the larger one the right 

 gill was free from the mantle. In the latter the anterior gills had free margins of 

 the reflected laminae, but the right one had coalesced to the body inferiorly; the 

 posterior gill of the right side was free, that of the left side attached to the ad- 

 duetor. In the small specimen both the anterior gills had their inner margins 

 attached to the sides of the body and, at the triangulär lobe, for a short space to 

 each other, but the anterior gill of the right side was free from the body above; 



