MACDONALD 
9 
example of this genus*, which I collected myself on the Wreck Reef, I found that all 
my previous remarks on its anatomy were correct, save that the lingual membrane was 
stated to support a " multiserial pavement of minute teeth." Employing a one-sixth -of-an- 
inch objective (Boss), I discovered my mistake with regard to this very small strap ; and 1 
think I may now very safely say that it is septiserial ; and so far, indeed, Tr if or is agrees 
with Cerithium. But when we take its otoliths, retractile proboscis, and lateral labial 
plates (composed of amber-tinted rhomboidal cells) into consideration, a place near Triton 
or Rauella can scarcely be denied to it. I am still convinced that the early state of its 
shell affords only an apparent mark of affinity to Cerithium. On the other hand, thr« <• 
openings homologous with those of Triforis are strikingly apparent in some JEUmellid ce . 
Having made one flagrant mistake, however, with regard to Triforis, I feel now rather 
disposed to leave the determination of its true status to more able malacologists, throw- 
ing out one hint — that its operculum is pointed, with an apical nucleus, as in Cerith i '■< 7 psis 
(Forbes), which also possesses a retractile proboscis. 
An error of observation is far more unpardonable than the false determination of thi 
genus to which any particular shell may appear to belong ; for it often happens that in 
the short but indefinite descriptions of the shell-characters given by authors, perspicuity 
is sacrificed in the attempt to attain conciseness. On this account I fell into another 
mistake, confounding a short and stumpy Fasciolaria, having very obscure plates on tin 
pillar, and a crenulated outer lip, with Swainson's Tritonidea, which has now become 
synonymous with Fisania. The operculum in both genera is stout and claw-shaped, and 
the animals themselves are not at all unlike each other. 
The lingual dentition of Fasciolaria, Fusus, and Clavella, however, may be at once 
distinguished from that of Fisania, which I believe to belong properly to the Buccinidw 
and not to the Maricida, if the Buccinum cinctum of Quoy, and Fusiostema of Swainson 
may be taken as true examples. 
So far as I have been able to discover, besides Mures itself, Bemifusus (Sw.) is the 
only genus, in the whole of the MunckUs, having an operculum with an approach to an 
apical nucleus, which is essential to Fisania. 
The family-difference observable in the dentition of the Buccinidce, Fusida, and Mnri- 
cidce is so distinctive, that, when once recognized, no confusion of the species of one family 
with those of another can possibly occur ; and thus an unfailing guide is afforded in the 
determination of doubtful cases, which may be more or less conformable with the defini- 
tion of Fisania or any other ambiguous genus. 
I leave the case of the Aeiculidcef an open question until I shall have the opportunity 
of comparing the anatomy of Geomelania and Acicula with that of JSgea (Benson ?), which 
I think may possibly be identical with the former genus; and if so, it will bring along 
With it some freshwater and littoral genera, viz., Kfdrobia, Syncera, and a number oi 
beautiful little Faludina-]ike shells now placed in the Fissoidce. 
Truncatella is doubtless close at hand, though perhaps sufficiently distinct to form the 
* 
Having obtained a second dextral Triforis at Moreton Bay, it may be safely stated that the shell is not invariably 
sinistral, though commonly supposed to be so by conchologists 
t As accepted by Mr. Woodward. 
