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SUMMARY OF CURRENT RESEARCHES RELATING TO 
prolonged forwards on the ventral surface to form a collar. The 
pharynx is eversible and richly ciliated ; there is a single pair of 
thoracic nephridia which open to the exterior in the second segment, 
reach back into the sixth, and then bend forward again. The giant 
fibres are minute, and there is in each nerve-cord one near the upper and 
inner surface. The dorsal “ cirri ” form a sort of collar in the second 
segment. 
Classification of Earthworms.* — Dr. W. B. Benliam has published 
an interesting “ attempt to classify earthworms.” He begins by offering 
some suggestions as to the nomenclature of certain organs. He proposes 
to use the term “ couple ” in place of “ pair ” when speaking of the 
arrangement of the setae which is found in Lumbricus , and in place of 
“ dorsal ” and “ ventral ” to use “ outer ” and “ inner.” He regards the 
peristomium as the first somite. In referring to the position of an 
aperture between two somites he uses the form x/xi. When the 
“ clitellum ” is equally developed all round the body it may be called 
the “ cingulum.” The terms “ vesiculae seminales ” and “ seminal 
reservoirs ” are conveniently replaced by “ sperm-sacs,” the “ recep- 
tacum ovorum ” by “ ovisac,” and “ vas deferens ” by “ sperm-duct.” 
The term “ capsulogenous gland ” is misleading, and may be replaced 
by Yejdovsky’s term “albumen-gland.” Such anterior nephridia as are 
used, not for excretory purposes, but for softening or otherwise acting 
on the food, may be called “ pepto-nephridia,” and they are either intra- 
buccal or extra-buccal. 
In the alimentary canal the following regions may be distinguished : 
buccal region, pharynx, oesophagus, gizzard, tubular intestine, and sac- 
cular intestine ; there are often two or more gizzards, and in some cases 
there is none. The typhlosole is absent in a few cases only. The 
calciferous glands are very frequently absent, and when present are very 
variable in number and position. 
The class Oligocileta may be divided into two sub-classes, accord- 
ing as asexual reproduction is or is not effected. 
Sub-olass I. Naidomorplia. 
Order 1. Naidina, with the families Aphanoneura, Naididae, 
Chaetogastridae, and the genus Ctenodrilus. 
Sub-class II. Lumbricomorpha. 
Order 1. Microdrili (Lumbricomorpha minora), with the 
“families” (Vejdovsky) Discodrilidae, Enchytraeidae, 
Tubificidae, Phreoryctidae, and Lumbriculidae. 
Order 2. Megadrili (L, majora). 
These may be divided into two branches, the first of which is called 
Plectonephrica, in consequence of the excretory system being in the 
form of numerous delicate tubules in each somite, which unite to form a 
network with more or less numerous external apertures ; a large 
“ nephridium ” with coelomic funnel may be present in addition to these 
tubules ; in this are the families Typhoeidae, Acanthodrilidae, and 
Perichaetidae. 
In the second branch, that of the Meganephrica, the excretory net- 
work is absent, and replaced by a pair (rarely two pairs) of large 
* Quart. Journ. Mier. Sci., xxxi. (1890) pp. 201 315 (86 ligs.). 
