ZOOLOGY AND BOTANY^ MICROSCOPY, ETC. 415 



the buccal organ, {h) Herbivorous, carnivorous, and omnivorous forms 

 occur, Cryptochilum, Paramsecium, Colpoda, Tillina, Colpidium, and 

 Vorticella feed on scbizomycetes and small zoospores, thus purifying the 

 water from Bacteria, Vibriones, Bacilli, and other microbes. Stentor, 

 Euplotes, many Oxytriclias are omnivorous, while Euchelys, Didinium, 

 Lacrymaria, Leucophra, Trachelidse, and Coleps are carnivorous, though not 

 despising zoogloea. (c) The herbivorous population is followed by the 

 carnivorous with approximate regularity. Guleps hirtus can in a few days 

 clear off a dense population of herbivorous forms. 



(d) M. Maupas has carefully studied the reproductive powers of 

 StylonycMa pustidafa throughout many generations. In favourable nutritive 

 conditions this species divides once in 24 hours with a temperature of 

 7°-10^ C, twice at 10^-15°, 3 at 15^-20^, 4 times at 20°-24^ and 5 times 

 at 24°-27°. At a temperature of 25°-26'' C. a single StylomjrUa would in 

 4 days have a progeny of a million, in 6 days of a billion, in Ih days of a 

 hundred billion. In 6 days the race would weigh 1 kg., and in 7^ days 

 100 kg. (e) With a vegetarian diet, however, the rate of reproduction 

 is much less, and the size smaller. (/) Light seemed to have no influence 

 on the development. Statistics are given for a large aumber of forms. 



Protozoa of Marseilles.* — MM. P. Gourret and P. Eoeser give an 

 account of the Protozoa found by them in the old port at Marseilles ; of 

 the fifty-eight species which they enumerate twenty are new, and there are 

 also some new varieties ; they divide the localities examined into twenty, 

 and point out that, where the waters are almost normal in character, there 

 are both few species and few individuals as compared with stations where 

 the water is putrid ; among the stations of putrid water it seems that the 

 number of forms increases with the foulness of the water, though there are, 

 of course, limitations to this. 



(1) The Holotrichous Infuso7-ia. — Paramsecium pyriforme is a new 

 species, varying in size, pyriform in shape, and with the mouth placed at 

 the bottom of a groove which passes obliquely from right to left ; there is 

 a pharyngeal swelling, infundibular in shape, and continued into a short 

 narrow cylindrical tube, which opens freely into the endocyte or central 

 protoplasm. It is not possible to distinguish the oral cilia from the 

 ordinary cilia of the cuticle ; trichocysts do not seem to be present. The 

 anterior contractile vacuole appears to be, and the posterior not to be constant; 

 micrococci may often be seen in the clear parenchyma. This new species 

 seems to be most nearly allied to P. chrysalis var. viridis. Placus sfriatus, 

 first found by Cohn near Breslau, and Nassula flava are next described ; of 

 the latter Chilodon ornatus and N. aurea appear to be synonyms. Enchelyodon 

 striatus sp. n. is flask-shaped, with a short neck, and a slight anterior 

 swelling at the top of which the mouth opens. It moves very slowly, but 

 its neck is very mobile and extensile ; the cuticle is marked by two sets of 

 striae, one longitudinal and one transverse ; the covering cilia are very short, 

 but around the mouth the cilia are longer and more vigorous ; the contractile 

 vesicle is irregular in form and very large ; this species seems to be nearest 

 to E. elongatus. A new variety of Metacystis truncula is described, and is 

 called variety crassa. The next three forms noticed are TracJielocerca 

 phsenicopterus, Lacrymaria co7-onata, and Chcenia teres ; of Amphileptus there 

 are two new species — A. lacazei and A. masslliensis ; the former is provided 

 with special long vibratile cilia, in addition to others arranged in tufts ; 

 these are separated from one another, and are ordinarily placed in the 

 interspaces between the tufts ; they appear to be specially useful in move- 



* Arch. Zool. Exper. et Gen., iv. (1886) pp. 443-534 (8 pis.). 



