ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
605 
nepliridia in oacli somite. Here are the families Moniligastridae, 
Eudrilidae, Perionycidae, Geoscolecidae, Rhinodrilidae, and Lumbricidae. 
The author next gives an account of the families and genera in 
extenso , and next a tabular summary of generic characters, with an index 
to the identification of genera. 
An attempt is next made to discuss the phylogeny of the group of 
earthworms — the excretory system, the setae, clitellum, prostate, and 
sperm-ducts may be taken as the more important characters. 
The results arrived at are indicated by this phylum : — 
Perionycidae ^Rhinodrilidae 
Lumbricidae 
Eudrilidae 
Moniligaster 
Gcoscolecidae 
/ 
Lumbricomorpha minora 
Atrium or Prostate.* — Dr. W. B. Benham raises some objections to 
Mr. Beddard's suggestion that the “ prostates ” of many earthworms are 
homologous with the “ atria ” of the Tubificidae and other freshwater 
Oligochaeta. By the term prostate we ordinarily understand a glandular 
structure which secretes a fluid, which is utilized in some way or another 
— how is not thoroughly known in Oligochaeta — in the process of copu- 
lation. It is admitted that the organs in question have some such 
function, and it seems better to retain the word prostate than to replace 
it by the ill-defined term atrium. Mr. Beddard, indeed, would seem to 
regard the epiblastic prostate of Tubifex as the homologue of the meso- 
blastic covering of the atrium of Moniligaster. 
Anatomy of Moniligaster .| — Mr. F. E. Beddard gives an account of 
the structure of Moniligaster , which, in his opinion, is not an earthworm 
except in habit. It differs from all earthworms in the following points : — 
The vas deferens is single on each side ; it only occupies a single seg- 
ment, or at most two ; there is only a single pair of testes ; the sperm- 
sacs are a siugle pair with a simple cavity, that is, one not divided up by 
trabeculae ; the atrium opens on to segment x/xi, and its structure is that 
of the atrium of Bhynchelmis ; the oviduct opens into segment xi ; the 
clitellum occupies segments x-xiii ; the egg- sacs are very large, and 
occupy about three segments. In these points Moniligaster approaches 
* Zool. Anzeig., xiii. (1890) pp. 368-72. 
f Proc. Roy. Sue. Edinb., xvii. (1890) pp. 5-7. 
