SOME NEW AND RARE CEPHALOPODA. 113 



the Argonaut ; there are fifteen pairs in each gill. The peritoneum, or external mem- 

 brane of the viscera, was remarkably mottled with large purple-red spots : I have ob- 

 served the same disposition of a brown pigment on the peritoneum in the Argonaut(s\ 



The pigment which gave the purplish tint to the skin when the animal was alive, 

 appeared to have been driven from the surface; for on removing the cuticle, which was 

 remarkably thick and elastic in this small Cephalopod, only some small brown spots 

 were perceptible in the vesicular 7-ete mucosum : these were aggregated chiefly on the 

 dorsal aspect of the body and head. 



As the generative organs were scarcely developed in either of the specimens, it is 

 probable that they may not have arrived at maturity, and the species consequently may 

 be assumed to attain a greater size than that of the largest individual in the collection, 

 which measures only 1-i- inch from the bottom of the sac to the extremity of the longest 

 arm. The prominence of the eyes, the structure of the funnel, the proportions of the 

 arms, and the partial development of the interbrachial web, will however afford the 

 means of distinguishing this species when it is again met with. 



The very interesting specimen of the Paper Nautilus, or Argonaut, which forms part 

 of Mr. Bennett's collection of Cephalopoda, is thus noted in his journal : — 



"March 7th. Fine weather ; light and moderate south-east trade breezes ; therm, 

 from 81 to 84 ; lat. 4° 43' south, long. 17° 37' west. I did not capture a single spe- 

 cimen with the net during the day ; but at 8 p. m. I procured some small specimens of 

 Exocetus, and also an excellent specimen of an Argonauta : on placing it in sea-water it 

 expanded its tentacula, but did not attach itself to the glass, or move about. Early on 

 the following morning I found the animal dead in the glass of sea-water in which I had 

 placed it on the previous night, and on moving the shell to take it out, the soft parts fell 

 out. After the animal was out of the shell, a cluster of ova was seen attached to the in- 

 voluted part of the shell ; somewhat resembling, but in the recent state more beautifully 

 shown than in, the engraving of apparently a similar specimen in the Appendix to 

 ' Tuckey's Narrative of the Congo Expedition.' On placing the shell in spirits, the 

 cluster of ova floated out like a diminutive plant of a pure white colour, presenting a very 

 elegant appearance. After being preserved a day in spirits, much of this beautiful ap- 

 pearance was lost. The body of the animal was of a dark reddish colour, which colour 

 was also given to the upper part of the shell, either naturally or imparted to it by the 

 animal ; the remainder of the animal was of a dirty white with minute purplish dots ; 

 and the arms were also speckled underneath of a similar colour : the suckers were white. 

 These cephalopodous animals are not (and I consider correctly) regarded as the true 

 inhabitants of the shell, but merely parasitical inhabitants ; and the animal not having 



' A development of pigment on the serous membrane of the abdomen is observable in many fishes, and in 

 some reptiles, as Anguis fragilis, Ophisarus ventralis, and some species of Lacerta, Cuv., and in Agama atra, 

 vi'here the peritoneal pigment is almost black. 



o 2 



