64 EARTHWORMS OF WEST INDIES. [CH. I 



the outlet of the sperm ducts and often a series of glands 

 which have been called for want of a better name " copu- 

 latory " glands which show a structure identical with that 

 of the glands at the end of the male ducts. In tropical 

 South America and in the West Indies are the following 

 genera belonging to this family : — Oeoscolex, Anteus, • 

 Rhinodrilus, Urobenus, Pontoscolex, Onychochxeta, Tricho- 

 chceta, Diachmta, Tykonus. These genera, if they possess 

 spermathecse, which they do as a rule, have them paired as 

 in the majority of earthworms. A representative of this 

 group Sparganophilus has been lately discovered by Dr 

 Benham in the Thames, and Griodrilus, usually referred 

 to the Lumbricidse, perhaps belongs to the group, though 

 its position cannot be at present regarded as certain. It 

 is likewise European. It is a remarkable fact that 

 the West Indian genera present considerable differences 

 from the genera found on the mainland of South 

 America. All of them, viz. Pontoscolex, Onychochwta, 

 Diachceta and Trichochceta have always, or nearly always, 

 the setse throughout the body or of the posterior segments 

 arranged in an irregular fashion though there are only 

 the usual eight per segment. The existence of peculiar 

 American forms in the West Indies and of peculiar 

 African forms in Madagascar is paralleled in other groups 

 of the animal kingdom. Pontoscolex it is true also occurs 

 in South America ; but it is so universally distributed a 

 form that its exact habitat is a matter of some doubt and 

 may as well be the West Indies as any other place. On 

 the hypothesis that the Geoscolicidae are comparatively 

 speaking a modern group, their total absence from the 



