SMARAGDINELLA. 257 



The exterior of this species has the general form of Scaphander 

 nobiiis, but the minute sculpture and the characteristics in detail 

 are alike distinct. 



Additional and mature specimens of this species appear in the 

 collections of 1878-79, from Station 162, off Guadeloupe, in 734 

 fins., fine gray mud ; bottom temperature 40*0. These specimens 

 show that the truncation of the axis is a character of the immature 

 shell, and that the adult shows nothing of it, but has the body from 

 one end to the other supplied with a broad solid flattened callus, 

 which is especially protuberant (into the aperture) at the beginning 

 of the posterior third. The outer margin of the callus has a sigmoid 

 curve parallel with the inner outline of the columella and body ; the 

 inner margin is, however, somewhat irregularly transversely 

 wrinkled, the mass of callus is much thicker in the middle third, 

 and its surface is ornamented with flattened pustula? irregularly dis- 

 posed. This gives to the shell an abnormal appearance, which I 

 took, in the single large (but as we know, immature) specimen 

 referred to in the description, as an indication of disease in the in- 

 dividual. More material shows these characters to be normal and 

 constant in their general features in the adult shells. The form of 

 the aperture is well shown in the figures ; its anterior portion is very 

 oblique, a feature only visible in a side view. 



The type species, Sabatia isseli Bellardi, bears no special resem- 

 blance to this shell ; it is of quite different shape, sculpture, and pro- 

 portions, with a callus more simple and proportionately less developed. 

 In the latter a minute dimple indicates the position of the wholly 

 immersed apex in the adult, while inr'the young the rough callus, 

 though thin, is distinctly apparent in a specimen only 4'0 mm. 

 long, and which has the nucleus and about three turns visible on the 

 apex. The nucleus is reversed and half immersed, smooth and 

 translucent. It is not wholly covered by callus until the shell is 

 more than 7'0 mm. in length. When half covered it resembles the 

 genus Cryptaxis of Jeffreys. The sculpture in the very young is the 

 same as in the adult. Scaphander niveus and gracilis of Watson 

 probably belong to this group. (/)//.) 



Genus SMARAGDINELLA A. Adams, 1848. 



Smaragdinella A. AD., Appendix to Capt. Belcher's Narrative 

 of the Voyage of H. M. S. Samarang ii, p. 475, 1848. Type Sulla 

 viridis Q. H. & A. AD., Gen. Rec. Moll, ii, p. 22. Glauconella 



