758 SUMMARY OF CURRENT RESEARCHES RELATING TO 



the water unless torn to pieces by violent freshets. He believes that 

 the whole of the sarcode retires into the statoblasts, from which it 

 issues again in spring. 



Protozoa. 



New Infusoria. — Dr. A. C. Stokes describes * a new genus and 

 six new species of fresh-water Infusoria. 



Hymenostoma n. gen., H. Jiymenophora resembling Lemhadion. 

 Trachelophyllum vestitum with needle-shaped objects scattered through- 

 out its substance which may be trichocysts, but their form and the 

 action of the light suggest that they may be crystals. They closely 

 resemble the acicular raphides of Lemna and other plants. T. tachy- 

 blastum, the specific name of which (" sprouting quickly ") was 

 suggested by the rapidity with which the animal repaired an injury 

 it sustained by a collision with an Oxytricha. Litonotus pleurosigma 

 resembling L. fasciola but diflfering from it and all other species of 

 the genus in the multiple contractile vesicles. L. helus and Petalo- 

 monas disomata. 



A new species of Vorticella ( V. Lochiooodii) is also described f by 

 the same writer. The characteristics by which it may be . dis- 

 tinguished from all Vorticellce are the existence and structure of the 

 cuticular prominences and the undoubted presence of two contractile 

 vesicles. 



J. P. McMurrich describes | Metopus striatus which he considers 

 to be sufficiently distinguishable from the other s^Decies (M. sigmoides) 

 to justify its being treated as a distinct species. 



J. G. Grenfell records § four new Infusoria from Bristol ; Zootham,' 

 nium Kentii differing from Z. dichotomum and all other species of the 

 genus in the characteristic covering of flocculent matter ; Pyxicola 

 annulata \\ very like P. Garteri, but differing in dimensions and 

 undulations ; Platycola hicolor, so named " from the two colours of 

 the lorica " (lorica dark yellow, with a colourless neck) — it has a 

 very delicate membranous hood which has a large oval opening, is 

 retractile, . and projects backwards from the top of the ciliary disk 

 covering the opening ; P. aurita (n. sp. '?). 



C. L. Herrick describes ^ Ojpliridium prohlematicum and an infu- 

 sorian closely related to Paramcecium, but differing in several inter- 

 esting particulars from it and its allies. In form this animal is 

 linear lanceolate (about 0*2 mm. long), tapering posteriorly to an 

 almost acuminate point. Anteriorly is a long vibratile proboscis, or 

 flagellum, which exceeds, when extended, the whole length of the 

 body. The mouth is situated at the base of this proboscis, and opens 

 into a very short infundibulum. The whole surface of the body and 

 proboscis is covered with minute cilia, which are inserted in rows, 



* Amer. Mon. Micr. Journ., v. (1884) pp. 121-5 (9 figs.), 

 t Amer. Natural., xviii. (1884) pp. 829-30 (2 figs.). 

 t Ibid., pp. 830-2 (1 fig.). 

 § Journ. of Micr., iii. (1884) pp. 133-8 (1 pi.). 

 II But see Dr. Leidy, this Journal, iii. (1883) p. 77. 

 If Science, iv. (1884) p. 73. 



