38 
laticaudata^ndiOlphi, 1819a (? type of Histiocephalus Diesing, 1851). 
Mueller, 1869 {Myzomimus Stiles, 1892). 
contorta Rudolplii, 1819a {Spiroxys Schneider, 1866). 
Beside all the genera thus far mentioned, a zoological revision of the 
threadworms must also take into consideration certain other genera, 
such as Physcdoptera (which some authors classify in the Filariidse^ 
others in the Strongylidde^ others as a distinct family), and several 
other genera, the systematic position of which is not definitely estab- 
lished. Thelazia Bose, 1819, based upon T. rhodesii (compare laci^y- 
malis) of cattle, must be considered in this connection. 
Without attempting at present to revise the entire filaria group, 
which should probably be given superfamily rank, as Filarioidea, it is 
possible, in light of the type Filaria as now determined, to clas- 
sify, to at least some extent, the threadworms reported for man. At 
least two subfamilies should be recognized for these worms, namelj^, 
Fracunculiinse and Filariinse. 
Superfamily FILARIOIDEA new group. 
Family FILARIIDA^ Braun, 1895. 
1863: Filaridea Carus, 1863, 461. 
1876: Filariadse heuckart, 1876a, 609-611. — Braun, 1883a, 160, 181. — Parona,1887, 358. 
1879: Filaridse Cobbold, 1879b, 5. — Blanchard, 1895, 746. — Bos, 1894a, 218. — Braun, 
1895b, 219. — Daniels, 1898e, 879-880. — Lepri, 1898a, 56. — Roger, 1901, 95. — 
, Schneidemuehl, 1896, 306. — Stossich, 1898, 92. 
1895: Filar iidse Braun, 1895b, 212-213. — Ransom, 1904, 20, 30, 31, 38, 40, 41. — Ship- 
ley, 1896, 147. 
1899: Filarides Assenova, 1899, 104. 
It is very difficult at present to write a satisfactory diagnosis of this 
family, but the following may Ije taken provisionally for this purpo.se: 
Family diagnosis. — Nematoda, Filarioidea: Body filiform, rather long, in some 
cases about a meter in length. Head straight, often, if not always, with two latero- 
median and four submedian papillae; lateral lines more highly developed than 
median lines. Mouth terminal, variable, in some cases with two lips, occasionally 
with a more or less distinct buccal capsule; esophagus slender, elongate, may be 
divided into two portions, but has no posterior liulb; midgut present; rectum pres- 
ent; anus subterminal. All species parasitic. Development, at least in certain 
species, with change of host. 
Male: With 1 to 2 unequal spicules; tail usually curved spirally, provided with 
papillae, and in some cases with lateral ahe. 
Female: Larger than male; vulva present or absent in gravid worms; when present, 
usually anterior; uterus double; usually ovo viviparous. 
Type genus. — Filaria Mueller, 1787. 
This family contains numerous species which have been placed in 
rather poorly defined genera. 
There can be little doubt that the Filariidde, must be divided into 
several subfamilies. The typical subfamily will necessaril}^ be Fila- 
riindd^ although the exact characters and extent of this subgroup can 
