Introduction to Animal Morphology. 69 



may be, as Agassiz supposes, early stages of Trematode 

 worms. 



2. Peridiniaea — mouthless (mouth-bearing, Schmarda), free, 

 loricated forms, with a transverse ciliated furrow, no con- 

 tractile vesicle, but with a nucleus, vacuoles and chlorophyll 

 granules. Some have a red pigment spot (Glenodinium) ; 

 others have two or three long, curved, horn-like processes 

 (Ceratium). The lorica is often double, chitinous (or siliceous ?). 

 Many are marine, and vividly phosphorescent ; they multiply 

 by longitudinal or transverse fission, and have been seen full 

 of globules {Pcrfy). Baihy regards some of these as Annelid- 

 larvae. They unite Flagellata and Infusoria. 



3. Acinetina — stalked, membrane-clad forms with radiant, 

 retractile, tubular processes, whereby nourishment is sucked 

 in (hence called Suctoria by Claparede, and Polystoma by 

 Greene). The stalk is an extension of the cuticle, and is 

 sometimes striated. The processes may be branched (Den- 

 drocometes),*' or in bundles, especially when the body is 

 lobate ; sometimes only one suctorial arm may exist (Rhyncheta, 

 parasitic on Cyclops). The endosarc contains granules, and a 

 nucleus with apparently an investing membrane. The 

 ectosarc includes one or more contractile vesicles. By the 

 processes which the animal applies to its host, currents of food 

 granules enter and coalesce within into food globules. They 

 multiply by gemmation, rarely by fission. We know little of 

 their life-cycle. Some are, perhaps, as Stein supposes, larval, 

 but this is denied by Claparede and Lach?nanti. Eberhard saw 

 one form becoming ciliated and changing into Bursaria 

 truncatella. Ophryodendron is commensal with Plumularia, 

 and has two classes of zooids, proboscidean and lageniform, 

 both mounted on curved stalks. 



4. Stomatoda includes the mouth-bearing forms, and con- 

 sists of four sub-orders :— I. Peritricha, with a ciliated peri- 

 stome, including five families : — i. Vorticellidae (Fig. 8, C) — 

 stalked, bell-shaped forms, with mouth and anus opening inside 

 the peristome. The stalk may abort and the bell be sessile 

 (Scyphidia, Gerda), or it may be rigid, branched or un- 



* The larva of Spirocliona gemmipara [Stein) . 



