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Show 1889.] ANATOxMY OF GONATUS FABRICII. 127 the posterior end I regret my inability to give a satisfactory account of its distribution, and the more so since it would have been interesting to ascertain how far it agrees with what Brock l has indicated as the typical arrangement among the (Egopsida. All that I am able to assert is that this vessel does not branch until a distance of about 2 centim. from the heart ; at which point it bifurcates. It seems probable that these two branches represent the anterior and posterior aortse of Brock, in which case I have failed to discover the arteria genitalis ; this, however, is not much to be wondered at considering the state of preservation of the specimens. There were no aortic hearts to be seen in any of these vessels. The Vena Cava (v.c.) bifurcates on a level with the anterior part of the ventricle ; a branch passing to each branchial heart, at the entrance to which it is joined by a vein passing from behind forwards over the dorsal surface of the branchial heart (p.v.c). A third vein (o.v.), beset like the others with renal sacculi, passes over the dorsal surface of the left branchial heart and then turns downwards over the root of the left gill to join the other vessels entering the left branchial heart ; it probably comes from the ovary, but it was impossible to make this out with certainty. The right branchial heart (br.h.") is somewhat smaller and more distinctly quadrate in form than the left (br.h.1). Each of them bears upon its dorsal anterior margin a small flattened spheroidal pericardial gland (p.gl.). IX. Respiratory Organs. The Gills appear, on the whole, to be constructed on the same type as in Ommastrephes 2, as was noticed by Verrill. X. Excretory and Generative Organs. Regarding the Renal Organs nothing more of any importance was made out than has been noted above (p. 119). But little can be said regarding the generative organs. The two larger specimens which I examined were both females, as was shown by the presence of the oviducts (Plate XIII. fig. 3, od.). There are two of these, which are gently curved and pass forwards just external to, and on the dorsal surface of, the root of each gill. Their extremities are pointed and the opening is a slit on one side of the tip. Nidamental glands are present as two flattened sausage-shaped bodies, with their convexities directed towards each other, in the middle line. They present the usual lamellar structure. Regarding the male organs Verrill makes the following statements : - " The specimen is still immature, and probably only one year old. The spermary or 'testicle' is small (length 18wm, diameters 2 m m and 4mm), flattened, tapering backward, partly 1 Op. cit. p. 247. 2 Joubin, " Struct, et devel. de la Branchie des Ceph.," Arch. Zool. exp. (2) iii. 1885. |
