178 Dr. Wilh. Giesbrecht on 
view. Rostrum very prominent, beak-shaped. Abdomen 
4-jointed. Anterior antenne 13- to 16-jointed. Exopodite 
of posterior antenn shorter than penultimate joint. Siphon 
without tube. Mandible large, denticulated at the oblique 
apex ; palp rod-like, with scarcely plumose seta. Sete of 
maxilla not plumose. Swimming-feet: last joint of outer 
branch with 5, 4,4, 4 plumose sete, of inner branch with 
6, 6, 5, 4 sete. Terminal joint of fifth foot with three sete. 
& unknown. 
9. Rhynchomyzon falco, sp. n. 
9. Length 1:45-1:5 millim. Head triangular in dorsal 
view. Processes of thoracic segments largely produced ; 
anterior abdominal segments with similar processes. Furca 
as long as the last abdominal segment; length: breadth=3: 2. 
Anterior antenne 13- or 14-jointed; first joint with spine, 
last joint granulate. 
Distr. Naples. 
10. Rhynchomyzon purpurocinctum, Th. Scott. 
Cyclopicera purpurocinctum, Th. Scott, Eleventh Rep. Fish. Board 
Scotland, p. 209, t. iii. 
Q@. Length 0°85-1 millim. Head elliptical in dorsal view ; 
processes of thoracic segments much less produced than in 
falco, of abdominal segments nearly wanting. Furca longer 
than the last two abdominal segments combined, five times as 
long as broad. Anterior antenne 16-jointed ; first joint 
without spine, last joint not granulate. 
Distr. Firth of Forth, Mull; Naples. 
Genus 6. Ascomyzon, Thorell, 1859. 
@. Thoracic segments laterally rounded off. Rostrum not 
prominent. Abdomen 3-jointed. Anterior antenne 20- (21- ?) 
jointed. Exopodite of posterior antenne shorter than penul- 
timate joint. Siphon with tube. Mandible-palp rod-like, 
long, 2-jointed ; setee not plumose. Maxilla large; the two 
lobes unequal; sete not plumose. Sete of swimming-feet 
probably as in Cyclopicera. Terminal joint of fifth foot with 
two (three ?) sete. 
11. Ascomyzon Lilheborgit, Thorell *. 
Ascomyzon Lilljeborgii, Thorell, K. Svensk. Vet.-Akad. Handl. Stock- 
holm, vol. iii. p. 78, t.xiv.; ? Aurivillius, difv. K. Vet.- Akad. Férh. 
Stockholm, 1882, p. 105, t. xvi. 
* Another species of the genus, Ascomyzon calvum, Brady and Robert- 
son (Rep. Forty-fifth Meet. Brit. Assoc. 1876, p. 197), appears to have 
never been described. 
