462 Mr. A. Adams on two new species of Heteropodous Mollusca. 



loured, with the apical whorls yellowish -, last whorl ventricose 

 andecarinate,the surface finely reticulated. Aperture semi- ovate; 

 the outer lip slightly thickened and furnished with two lobes, 

 the anterior one simple and obtusely pointed; the posterior 

 folded in at the sides for the siphon, and truncate at the end. 



Many of the genera of Pteropods, both those with shells and 

 those with naked bodies, have been taken and recognized by me. 

 The species of Spinalis also sometimes abound. The figures 

 both of D'Orbigny and of Eydoux and Souleyet are very good ; 

 others are bad, and fail to give any idea of these forms wlien 

 living; but a ship, unfortunately, is a bad place either for draw- 

 ings or for peaceful study. 



Rio de Janeiro, 4th Feb. 1857. 



Since my last brief communication I have been fortunate 

 enough to detect a second new species of Macgillivrayia from 

 the Atlantic Ocean, which difi'ers from my M. ecJiinata in the 

 absence of spines round the last whorl, and in the colour, form, 

 and simple aperture, which is not armed at the fore part; from the 

 other species of the genus it may be readily known by the upper 

 whorls being crowned with seta3. It may be thus characterized : 



Macgillivrayia seiigera, A. Adams. 



M. testa subglobosa, cornea, semiopaca ; anfractibus quatuor, ultimo 

 amplo, laevi, inermi, penultimo in medio angulato, serie setarum co- 

 ronato et longitudinaliter delicatim costulato ; nucleo subvioiaceo. 

 Apertura ovali, antice simplici, rotundato. 



Hab. in Oceano Atlantico Australi. 



Shell subglobose, horny, semiopake; whorls four, the last 

 large, smooth ; the penultimate angulated in the middle, and 

 furnished with a series of bristles directed nearly upwards, very 

 finely longitudinally costellated ; the nucleus violaceous. Aper- 

 ture wide, simple anteriorly. 



Numerous interesting forms of pelagian Crustacea have been 

 captured during our delightful passage from Madeira to Eio, 

 among which was a specimen of the Rhabdosoma armatum of 

 Adams and White, two species of Oxycephalus of Milne-Edwards, 

 Squillerichthys, Oplophorus, Megalopa, Zoea, and many others. 



The Glaucus was taken in some numbers ; it has the means 

 of distending its body with vesicles of air disposed along the 

 front part of the back, to enable it to float the better. When 

 becoming languid, it protrudes a long, pale, dilated proboscis : 



