4 ZOOLOGY OF THE VOYAGE OF H.M.S. SAMABANG. 



There is a considerable difference in the general aspect and disposition of the spots, &c, between the 

 animals of Argonaulce gondola and argo. In A. gondola the sac-like mantle is more ovoid and elongated ; 

 the head is narrower ; the funnel broader, shorter, and furnished, at the upper and anterior extremity, 

 with two conical elongations ; the eyes are considerably larger and slightly more prominent ; the tentacular 

 arms are much shorter in comparison and of greater width, more particularly at their basal portions ; the 

 suckers are much larger, more prominent, and placed closer together. This species varies also considerably 

 in colour from A. argo. The extremities of the brachia are marbled with deep red-brown, and, in the other 

 parts, are covered with large, irregular, oval, reddish blotches, each margined with a dark colour ; the 

 circumference of the suckers is marked with brown spots; the upper surface of the funnel is covered with 

 pale pink, rather scattered and irregular, quadrate blotches, margined with dark red-brown ; the mantle, 

 on the dorsal surface, is densely sprinkled with round and square spots of a chesnut-brown and crimson of 

 different sizes; the velamenta are minutely dotted with crimson and red-brown, and have a more bluish 

 tinge than those of A. argo ; the under surface is mottled and minutely dotted with dark chocolate on the 

 arms, and on the body is marked with small, irregular, dark red-brown spots. A. A. 



Plate I. Fig. 2 a. Animal swimming, embracing the shell with its velamenta. Fig. 2 b, the same divested of 

 its shell. Fig. 2 c to k, development of the ovum, — c, impregnated egg ; d, three spots appear ; e, head and mantle 

 indicated ; /, rudiments of brachia ; g, yolk-bag seen ; h, lateral view of the same. Fig. 2 i, egg-mass in situ ; 

 2 k, egg-mass unravelled; 2 I, front view of egg-mass. Fig. 2 m and n, aeetabida ; 2oandj9, the mandibles. — 

 Fig. 2 a, b, i, k, and I, of the natural size, the remainder more or less magnified. 



Plate IT. Fig. 2 q. Front view of a full grown specimen of A. gondola, from Mr. Cuming's Collection, showing 

 the outward extension of the auricles. Fig. 2 r, s, and t, lateral views of specimens of different ages. 



£. Argonauta hians. Arg. testa lateribus convexis, radiatim rugatis, rugis exiliusculis, vix undulatis, 

 alternis brevioribus medio descendentibus, carina lata, tuberculis compressis, aperturd subquadrato-oblonga, 

 auriculis simplicibus ; colore fuscescente. A. hians, MSS. Dillwyn, Desc. Cat. of Shells, vol. i. p. 334. 

 Argonauta nitida, Lamarck. 



Hab. South Atlantic Ocean. 



Several examples of this species, easily distinguished from the A. gondola by the following 

 characters, were collected in the South Atlantic Ocean. The wrinkles are more faintly 

 developed, the keel is not so broad, and the tubercles are much less prominent ; the auricles 

 are but slightly prolonged, and the shell has frequently a peculiar yellowish-brown glazy 

 appearance, which probably suggested the name given to it by Lamarck. Both animal and 

 shell have been figured by De Ferussac and D'Orbigny in the work already referred to. The 

 latter is here introduced for the sake of exhibiting a comparison of the species, and on account 

 of that work being so little known to English conchologists. The shell there figured as the 

 young of A. hians is our A. Owenii. 



Plate III. Fig. 2 a. Front view of the shell showing the aperture and simple auricles. Fig. 2 b and c, lateral 

 views of specimens of different ages. 



3. Argonauta Owenii. Arg. testa lateribus convexo-compressa, radiatim rugata, rugis angustis, 

 valde prominentibus, undulatis, alternis brevioribus medio descendentibus ; carina mediocri, fortiter tuber- 

 culata, tuberculis valde prominentibus; aperturd subangusta, auriculis simplicibus ; colore fulvo-fuscescente. 



Hab. South Atlantic Ocean. 



A. fine adult specimen of A. Owetiii (Fig. 1 b), collected by Mr. Cuming, has enabled us 



