MYXINE. 348 
Son diamétre est alors le dix-huitiéme ou a peu pres de sa longueur totale.” 
From Commerson he quotes directly “ Conger olivaceo-virens, immaculatus, 
lac et gluten plurimum fundens.” The name Mwrenoblenna was not 
approved by Rafinesque, 1815, who promptly changed it to Anopsus, with- 
out adding anything to a knowledge of the object to which the term was 
to be applied, and which he in the Analyse, page 93, placed in his sub- 
family Ap/leridia of his family Ophictia. On the next page, 94, he credits 
himself with Myzine, and with it and Gastrobranchus of Bloch forms his 
subfamily MWyainia of his family Cyclostomia. 
The specimens on which five of the species characterized below are 
based are those used by Putnam, 1874, for his Notes on the Myxinoids, 
where they were arranged as three varieties of a single species. The differ- 
ent types resemble one another so closely, and individual variation is so fre- 
quent that determination is a matter of some difficulty. In fact it is only in 
comparisons of many individuals that the distinctions become really appar- 
ent. Even when the averages are quite distinct the species may appear to 
overlap, through variations occurring in particular cases. In Myzine gluti- 
8.8 . 
sa elght 
nosa the dentition formula most common may be indicated by ; 
teeth on each side both above and below, while variations to one more or 
one less occur in the lower series and less frequently in the upper. JZ. U- 
mosa is better shown by the formula ,,, nine in each upper series and ten 
in each lower, while the most frequent variations add one more to each 
upper or subtract one from each lower series. MM. acutifrons has 33 varied 
by one more in each upper series or by one less in each of the lower. Either 
a OF qa will represent JZ. australis, and the variations include all pos- 
sible additions and subtractions of a single one from each series between the 
two formulz. All of these have the anterior two teeth of each series con- 
fluent at their bases. M/. tridentiger has ten or eleven teeth in each series 
but differs from the preceding in having the anterior three teeth confluent in 
their bases. J. circifrons has the formula {; of which the anterior three 
of each upper and the anterior two of each lower series are confluent. 
Again, if the mucous sacs, or the pores, are compared it is found that I. 
giutinosa has not as many in either the pectoral (from head to gill opening) or 
abdominal series (from gill openings to vent) as JZ imosa ; while M. australis 
is rather close to M. dimosa but has fewer pectoral and more abdominal pores 
than M. acutifrons. The species may approximately be distinguished by the 
following: 
