40 Proceedings of the Royal Physical Society. 
they agree in the form of the atria, in the fact that the 
nephridia do not commence until the xilith or xivth segment, 
in the absence or rudimentary condition of the gizzard, in 
the absence of penial sete at the male pore, which is in both 
upon the xviiith segment, and in a number of minor points. 
I believe that it is necessary to add a fifth species to the 
four above enumerated ; this is Cryptodrilus insularis of Rosa." 
Although the species is referred by Rosa to the genus 
Cryptodrilus, this is only done provisionally. As Rosa justly 
remarks, the genera of this family require revision. 
I place Cryptodrilus insularis in the genus Pontodrilus 
for the following reasons :—It has 
1. Setze in eight rows. 
. No dorsal pores. 
. Rudimentary gizzard. 
. No nephridia until the xiiith segment. 
5. Tubular atria, and no penial set. 
H OF dO 
This assemblage of characters distinguishes the genus 
Pontodrilus from any other genus; it comes nearest, of 
course, to the genus Megascolides; but differs in the fact 
that the nephridia do not commence at once (i.¢., in the iind 
or ilird segment). In the same point it differs from the 
genus Microscolez. It is true that the difference may not 
appear to be a very great one; but it is, considering the very 
large number of Cryptodrilids, and their similarity to each 
other, a good deal to have got one character running through 
a number of species, which also agree in other particulars. 
The five species may be thus distinguished :— 
Setze ornamented. P. arenae. 
Setze not ornamented. 
Gizzard completely absent. 
Two pairs of spermatothece.  P. hesperidum. 
One pair of spermatothece. P. phosphoreus. 
Gizzard rudimentary. 
Sete irregular behind. P. insularis. 
Setze regular throughout. P. littoralis. 
1 Die exotischen Territolen des k. k. naturhist., etc.—Ann. k, k. nat. 
Hofmus. , Bd. vi., 387, , ; 
