958 The American Naturalist. [November, 
ZOOLOGY. 
Thelohan on Coccidia.'—Thélohan describes a curious Cocci- 
dium (C. eruciatum) parasitic in the liver of Carang trachurus. g 
four spores are arranged in the form of a cross and the envelope of 
each spore is formed by two valves, which is art entirely new depart- 
ure for this genus. A Coccidium species (?) found in the livers of 
sardines and herrings was similar to C. cruciatum except that the cross 
arrangement of the spores was not noticed in any case. C. minutum, 
a new species from the tench, is also described. 
It has been proven that the species of Coccidium which infest rab- 
bits run through their spore stage after escaping from their hosts, but 
Thélohan has discovered the interesting fact that the new species which 
are here described, as well as C. sardine Th. and C. gasterostei Th. 
form their spores and sporozoites while still inside their host. With 
this change of habit the thick membrane of other species becomes 
unnecessary and in the species found in fish the membrane is in reality 
very thin. C. bigeminum of dogs lies between these two extremes, for 
the sporoblasts form while the parasite is still in the dog, but the spor- 
ozoites evidently do not form until the parasites escape from their host. 
In the same publication Thélohan describes “ Des Sporoziaries Indé- 
terminés Parasites des Poissons (pp. 162-170),” which are very diffi- 
cult to classify in the present system. They resemble Eimeria, but 
according to Thélohan the cyst contains a true nucleus as well as 
sporozoites, 
It will be rea eed that certain German authors now Fp to 
suppress Eimeria, since they believe that genus simply forms a stage 
in the development of Coceidiwm by “ gymnospores (Pfeiffer).” Should 
this theory be definitely established (contrary to Pfeiffer and others, we 
cannot consider it as yet definitely proven that Kimeria is identical 
with the gymnospore stage of C. oviformes), the “Sporozoaires indéter- 
minés” of Thélohan might bear the same relation to the fish coccidia 
that Eimeria, according to certain German authors, bears to the cocci- 
dia found in rabbits—C. W. S 
Recent Work on Parasites.—Dr. C. W. Stiles, of the Bureau 
of Animal Industry, has recently published several articles on para- 
*P. Thélohan, sur Quelques Coccidies Nouvelles Parasites des Poissons. Jour. de 
P Anat. et de la Phisiol., 1892, pp. 152171, Plate 12, 1-32. 
