380 
Parasitic Worms 
they give rise. In no department of preventive medicine is the statement that 
prevention is more useful than cure of greater applicability than in Helminth¬ 
ology, and no more striking instances of this could be wished for than such 
diseases as Ancylostomiasis and Bilharziasis. 
The importance of attention to minute structural and anatomical detail is 
well instanced by recent work on the Sclerostome parasites of horses. Where 
not many years ago only a dozen or so ill-defined and much-confused species 
were recognized, now there exists a large family with numerous genera and 
species. While this involves a much extended and possibly more cumbrous 
nomenclature it yet creates a greater simplification and precision of detail. 
On that account one must welcome such work as that of Beddard which 
though inclined to be prolix in certain respects is yet of the greatest funda¬ 
mental value. His work is probably amongst the best which has been done 
on Cestodes in this country. Another contribution on Cestode structure which 
appears to be of considerable importance is that of La Rue on the Cestode 
family Proteocephalidae. Although this work is to a large extent revisionary 
it constitutes a valuable summary of our knowledge of a somewhat unusual 
group. Of a similar character is Douthitt’s monograph on the Anoplocephalid 
family of Cestodes. This is of great importance to those who may be concerned 
with the tapeworm parasites of horses. 
A useful summarizing work is that of Krause on the Hemistomes, a group 
of Trematodes which is of considerable zoological interest though not of much 
pathological importance. Of equal merit and of much greater economic 
importance is Stunkard’s monograph on the Polystomidae, Aspidogastridae 
and Paramphistomidae of North America. Of some interest, too, is the embryo- 
logical work of Lepeskin on the ovogenesis of Zoogonus mirus , a peculiar 
ovoviviparous Trematode parasite of Mediterranean fishes. This parasite lends 
itself particularly well to such study and has been the subject of previous 
similar work by von Hofsten and others. 
These constitute perhaps the most extensive single works on Cestode and 
Trematode anatomy. On Nematode structure the work is considerably more 
voluminous but one can deal here with only a very restricted selection. 
Perhaps the most outstanding monograph is that of Martini on the anatomy of 
Oxyuris curvula, the large threadworm of the horse. Martini’s histological 
work is, of course, well known and this monograph constitutes a fitting suc¬ 
cessor to his earlier work on Ascaris. Of somewhat similar nature is Deineke’s 
histological researches on the nervous system of Ascaris hncgalocephala. The 
work of Neveu-Lemaire on the reproductive organs of the Metastrongylidae 
is also deserving of special mention as is that of Zacharias on the finer structure j 
of Ascaris from a cytological standpoint. Seurat’s monograph on the parasitic 
Nematodes of Northern Africa (1920) and Khalil’s revision of the Nematode j 
parasites of Elephants (1922) are two of the most important recent systematic 
works on Nematodes. 
Of more practical importance to the economic helminthologist is Hall’s 
