jan. — mar. 1857.] voyage from England to Madras. 16o 



luring any more Molltjsca, although many interesting forms of 

 Crustacea rewarded our efforts, a description of which is hardly 

 within the scope of these pages, which however, I trust, have suf- 

 ficiently shown, how the monotony incidental to a sea voyage may 

 be relieved by giving attention to Zoology, facilities for which pre- 

 sent themselves much oftener than might be imagined by those 

 who have not practically pursued such investigations. 



References to plates IX., X., XI. and XII, illustrating Mr, 

 Traill's paper. 



[ We had hoped to receive a synoptical table of the species collected by Mr. 

 Traill, but as he finds himself unable from the want of books of reference, to 

 assign the trival names of the several specimens or to pronounce with certainty 

 which of them may be considered new, the following list has been added to facili- 

 tate references to the Plates.] 



PLATE IX. 



Genus Aegonauta, 



Dorsal arms (of the female) webbed at the extremity, secreting 

 a symmetrical involuted shell. Mantle supported in front by a 

 single ridge on the siphon. 



Fig. 1. Animal of Argonauta sp. ? detached from the shell. Color 



light brown or horn color with crimson spots. 

 Fig. 2. The Shell. 



a. Front view, 



b. Lateral view. 

 All of the natural size. 



Genus Ianthina. 



Shell thin, trochiform ; nucleus minute, sinistral; aperture 

 foursided : column tortuous ; lip thin, notched at the outer angle ; 

 color violet at the base becoming white on the spire. 

 Fig. 3. Ianthina exigua (magnified). 



The small figure shows the natural size. 



Fig. 4. 1. fragilis. 



Fig. 5. I. — globosa. 



Genus Atlanta. 



Shell minute, glassy, compressed and prominently keeled ; 

 nucleus dextrally spiral ; aperture narrow, deeply notched at the keel ; 

 operculum ovate, pointed. 



Fig. 6. Atlanta (magnified). 



The small fig. shows the natural size. 



