TRITONIIDAE. 9 



They are yellowish brown, and the edges arc not black or denticulate. Tlic masticatory 

 process is very short and, as in many other forms, presents under a high power the 

 appearance of a tessellated pavement. 



The radula is of a mahogany brown, strong, and not at all fragile. It consists of 

 from 50-58 rows, each consisting of a broad rhachidian tooth (Fig. 6), a large first lateral 

 somewhat different from the rest (Fig. 7), and 60-70 hamate teeth (Fig. 8). The 



Fig. 5. — Tritoniella belli — Jaws. 



rhachidian tooth has a strong, pointed, elevated, triangular central cusp, and about four 

 rather irregular, not very pointed, denticles on each side. It seems to be a transition 

 between the form of tooth found in Tritonia (see particularly Marionia arhorescens in 

 Dr. Bergh's Fig. 34, pi. Ixxxviii., Make. Unters, part XVII., in Semper's Reisen) and 

 that found in Bornella, Pleurophi/Uidia, and NotaeoUdia. The laterals are rather thick 

 and clumsy, not much hooked, with small bases, and no kink in the back. The second 



Pig. &. — Tritoniella belli 

 Rhachidian Tooth. 



Fig. 1.— Tritoniella belli- 

 FiBST Lateral Tooth. 



Fig. 8. — Tritoniella belli — Three 



Laterals from the Middle of 



THE Half Row. 



lateral from the rhachis is lower than the others, and has a broader base, and these 

 features are much increased in the first, which, however, still preserves traces of the 

 hamate shape. 



The salivary glands consist of a thread-like duct and a long (as much as 24 mm. 

 in one specimen) flocculent mass. The oesophagus is short, and soon enters the 

 stomach, which has the appearance of a large tul)e, not much dilated, and never more 



