1912.] On a Gregarine present in Mid-Gut of Ceratophylli. 37 



could not be ascertained. The karyosome, which was already developed in 

 this young trophozoite, soon attains a considerable size. The septum, 

 dividing the protomerite from the deutomerite, appears later, when the 

 organism has reached a length of about 30-40 fi. 



During the early phases of growth in the larval gut, the trophozoite may 

 relax its hold of the epithelium, and may, later, renew its attachment, but 

 whether all the detached trophozoites succeed in refixiug themselves is not 

 clear (see footnote, p. 34). 



Systematic Position. 



The characters of the vegetative phases, cysts, spores, and sporozoites of 

 the Gregarine described in the preceding pages agree closely with those of 

 the genus Steinina, Leger et Duboscq,* which was defined in the following 

 terms : " Polycystidee de la famille des Actinocephalides, caracterisee par un 

 epimerite constitue d'abord par un court prolongement digitiforme et mobile 

 et plus tard par un bouton aplati. Developpernent a phases fixees pouvant 

 alterner avec des phases libres. Kystes sans sporoductes, a sporocystes 

 biconiques, fortement ventrus." The only feature in which the organism 

 described by us deviates from this diagnosis is the shape of the spore, 

 which is not strongly inflated. However, the difference in regard to this 

 character is so small that we do not hesitate to refer our Gregarine to the 

 genus Steinina. This genus has hitherto been represented by a single species 

 — S. ovalis (Stein) — recordedf from the intestine of the larva (meal-worm) of 

 Tenebrio molitor. Our specimens differ from this species in (1) the shape 

 of the spores, which are less strongly inflated ; (2) the size of the spores, 

 which are 11 to 12 fi long and about 7 ja broad (in S. ovalis they*are 9 long 

 and 7'5 /x broad) ; and (3) the younger trophic phases are usually less 

 elongate and more oval or spherical, and the sporonts (" sporadins ") are 

 more pyriform. These differences seem to us to be sufficient to justify the 

 formation of a new species, for which we propose the name Steinina 

 rotundata, for the specimens described in this paper. 



Steinina rotundata, n. sp. — Near S. ovalis, Leger et Duboscq, but the 

 spores are larger and less strongly inflated than those of the latter. In the 

 younger trophozoites, the protomerite and deutomerite together usually form 

 an oval or sub-spherical mass, but later the organism becomes more or less 



* ' Archiv f. Protistenkunde,' 1904, vol. 4, pp. 352 — 354, 2 figs. 



t See Leger and Duboscq, op. cit., in which the earlier records are cited. >S. ovalis has 

 also been recorded from the gut of the meal-worm by Kuschakewitsch ('Archiv f. 

 Protistenkunde,' 1907, Suppl. vol. 1, p. 203) and Pfeffer (op. cit., 1910, vol. 19, p. 108), and 

 its cycle of development has been studied by IVIavrodiadi (' Proces-verbaux Soc. Natural. 

 Varsovie,' 1909, vol. 21, pp. 106—118). 



