OF THE PHILODIN^A. 



705 



111 one siDecies, a tactile tube 



different views from the under side.) 

 1-120". ^ 



M. gracilis. — Has a more slender body 

 than the last, and two teeth in each jaw, 

 but no tube orspui". Length about 1-200", 



developed ova or male organs been observed 

 is present. 



MoNOLABis conica. — Stout, provided 

 with a tactile tube, or spur, and three 

 teeth in each jaw. Between the rotary 

 organs the brow can project and resemble 

 a proboscis, (xxxv. 485, 486 represent 



Genus PHILODINA (XXXY. 487-490; XXXYIII. 4). —Eyes two, 

 cervical, foot with horn-like processes. All the species possess two vibratile 

 or wheel organs upon the breast, and five of them have a frontal ciliated 

 proboscis. Longitudinal muscles are distinct in one species, and two for 

 moving the foot in six. The oesophageal bulb has foui^ muscles; its jaws are 

 two-toothed in four species, thi-ee-toothed in two species ; but in one species 

 the oesophageal bulb has not been satisfactorily seen. The alimentaiy canal 

 is filiform, vaih a posterior enlargement in six species ; in one it appears to 

 have pouches or pockets. The glandular or cellular mass suiTounding the 

 fiHform part of the canal sometimes becomes distinctly coloiu-ed when the 

 creatui^e eats coloured food, and therefore seems connected with the nutritive 

 system, and is probably a convolution of caecal appendages. Biliary (?) glands 

 are found in six species. The ovary developes eggs, which are usually extruded 

 before the young are hatched. Three species possess a contractile vesicle ; one, 

 vibratile tags. A tube, in some cases ciliated, is always present at the neck. 

 Transverse bands are seen only in P. erythrophtliahna. Eyes are found in 

 aU the species, and nervous ganglia connected with them in P. erythroph- 

 ihalma : sometimes the eyes are veiy pale ; hence a solitary specimen may be 

 mistaken for a CaUidina. XXXYIII. 14 is a diagram of the head of Phih- 

 dina as viewed in fi'ont, and fig 15 of the same viewed laterally. 



Philodina erythroplithalma (xxxA^n. 

 4). — White and smooth ; eyes roimd 

 hom-like processes of the foot short ; 

 jaws two-toothed. Foimd abmidantly 

 dm'ing the spring and summer in water- 

 tubs and amongst Confervse. In glass 

 vessels it increases rapidly ; and, if sup- 

 plied occasionally with two or three stems 

 of hay, the breed may be preserved for 

 years. It is often met with in vegetable 

 infusions of different kinds. 1-120" to 

 1-48". 



P. roseola. — Body smooth ; eyes oval, 

 hom-like processes of the foot short. 

 "I have observed," says Ehrenberg, "that 

 this animalcule, when kept in glasses, 

 deposits its eggs in heaps, and the parent 

 remains a long time with the young ones 

 produced from them, forming a sort of 

 family or colony, which cu'cumstance we 

 are not to be hindered from ascribing to 

 a sense of company or family, though the 

 pride of man may laugh at it." (xxxv. 

 490 represents one with the wheels ex- 

 tended.) 1-72" to 1-48". 



P. collaris. — Body smooth, hyaline, or 

 white, eyes round ; a prominent annulus 

 or collar sm-rounds the neck. It is 

 especially characterized by the extent of 

 the alimentary canal; and caecal appen- 



dages attached to it ; so that, when the 

 animalcule is fed upon indigo, it appears 

 polygastric. 1-120". 



P. macrostyla. — White and smooth, 

 with oblong eyes ; it has three teeth in 

 each jaw ; horn-like processes of the base 

 of the foot long. Foimd amongst Oscil- 

 latoriae. 1-70". 



P. citrina. — Smooth, citron-coloured 

 in the middle ; extremities white ; eyes 

 variable in form; horn-like processes 

 slightly elongated. Found amongst Os- 

 cillatoriae. 1-70". 



P. aculeata. — White, pro^-ided with 

 soft spines ; eyes round. The tactile tube 

 (antenna) is thickened anteriorly m a 

 globose manner; the jaws have each three 

 teeth, (xxxv. 487, 488 represent this 

 animalcule; and 489 the jaws and teeth 

 separate.) 1-70". 



P. megalotrocha. — White; body smooth 

 and short; wheels large; the proboscis 

 between them long; eyes oval ; jaws two- 

 toothed. Two straight setse at the end 

 of the tail. 1-216" to 1-108". 



P. hirsuta. — Of a pale yellow co- 

 lour, and covered with a short down ; 

 eyes oblong; foot prolonged by dorsal 

 spines; viviparous. Length 1-72"; of 

 egg 1-480". Berlin. 



2z 



