APPENDIX. 859 



Glenodinium Warmingii, Bergh. — Body suborbicular, compressed, about 

 twice as broad as long, subreniform as seen in horizontal section, divided by the 

 equatorial furrow into two distinct segments, the anterior one being much the smaller ; 

 cuirass membraneous, entirely smooth and homogeneous ; endoplasm orange- 

 coloured, inclosing chlorophyll, diatomin, and starch. Diameter of body 1-700" to 

 1-550". Hab. — Salt water : Baltic Sea. 



Genus Diplopsalis, Bergh. — Animalcules resembling those of Glenodinium, 

 the cuirass divided by a subcentral equatorial furrow into two subequal segments, 

 but neither reticulate nor separated into secondary plates or facets ; two delicate 

 membraneous crests, as in Dinophysis, developed from the sides of the longitudinal 

 furrow. 



Diplopsalis lenticula, Bergh. — Body depressed lenticular, subcircular in 

 horizontal optic section, the membraneous crests of the longitudinal furrow not 

 strengthened by decurrent linear thickenings ; endoplasm inclosing chlorophyll and 

 diatomin, also a large transparent vacuole, representing probably the contractile 

 vesicle. Diameter of equatorial region of the body 1-125". 



Hab. — Salt water : Baltic Sea. 



Genus Protoperidinium, Bergh. — Animalcules resembling short-horned or 

 cuspidate examples of the genus Ccratiiini, such as C. diver gens, but their horn -like 

 processes, which consist of excurrent developments of the edges of the longitudinal 

 groove, united by membraneous crests to the general surface of the cuirass. 



The membraneous crests developed as cuspidate processes of the carapace are 

 regarded by Bergh as modified homologues of the membraneous ventral plates of 

 JDi?iophysis, this last-named genus, in accordance with such interpretation, being thus 

 united to the typical genus Periditiium. 



In addition to the following newly discovered type he proposes to include in the 

 same genus the Peridinium (^Ccratiiim) Michaclis of Ehrenberg. 



Protoperidinium pellucidum, Bergh. — Body subspheroidal, divided into two 

 even areas by the subcentral horizontal furrow, with two anterior membraneous 

 cusps, the posterior extremity developed into an attenuate, terminally toothed, 

 acuminate extension ; cuirass composed of numerous finely reticulate facets. Length 

 of body 1-450". Hab. — Salt water : Baltic Sea. 



Genus Protoceratium, Bergh. — Animalcules resembling those of Periditiium^ 

 the cuirass divided by the equatorial furrow into two distinct segments, but these 

 segments simply reticulated and not separated into distinct secondary plates or 

 facets ; the longitudinal furrow, with the exception of the oral fissure and appended 

 flagellum, enclosed by the cuirass. 



Protoceratium aceros, Bergh. — Contour of body ovate or subspheroidal, 

 closely resembling that of Peridinium tabulatum, but the ventral aspect not so dis- 

 tinctly flattened or concave ; the entire surface of the cuirass finely reticulate but not 

 subdivided into distinct parts ; endoplasm inclosing chlorophyll, diatomin, and 

 apparently starch-like corpuscles ; often with an eye-like pigment-spot. Length of 

 body 1-700". Hab.— Salt water : Baltic Sea. 



Ceratium hirundinella, Miill. sp. — This species has been described in 

 Vol. I. p. 457, in connection with the title of Ceratium longicorne conferred upon it 

 by Perty. Bergh, however, would appear to be justified in identifying it with the 

 Bursaria hirundinella of O. F. Miiller, originally passed over by the author as pro- 

 bably representing the larva of some Turbellarian such as Monostomum, and this 

 specific name must consequently take the precedence. The so-called Ceratium 

 hirundinella of Dujardin is, as already shown at p. 462, identical with the Peridinium 

 {^Di?nastigoaulax) eor/iutum of Ehrenberg. 



Polykrikos auricularia, Bergh. — Body subcylindrical or barrel-shaped, with a 

 scalloped or crenated lateral outline, obtusely rounded at the two extremities, about 

 two and a half times as long as broad, indented along the centre of the ventral 



