Hj/dathiaea.'] infusoeial animalcules. G39 



NoToiiMATA vermicularis(Dni.) —Body vermiform, very coutractile ; of 

 variable form, with a kiducy-shapcd red speck, in which is partly 

 imbedded a white transparent globule. Length 1-11 8th. Found 

 in the Seine. 



Genus Synchaeta. The Iristle-headed Rotatoria have a single 

 cervical eye ; compound rotatory organs, of six to ten lobes, and 

 armed with from two to four styles ; foot furcate. The strong styles, 

 or bristles, arc situated between the clusters of cilia, and, probably, 

 act as organs of prehension ; the body is very short, and broad 

 anteriorly, tapering to a point posteriorly, so as to resemble a cone. 

 Internal longitudinal muscles exist in all the species ; those of the 

 foot arc seen in three species : the oesophageal head is large, with 

 single-toothed jaws, and exists in all the species ; but in two only is 

 the whole chewing apparatus distinctly seen. The thin oesophageal 

 tube is long in two species, short in the rest ; it leads to a simple, 

 wide, conical, alimentary canal, which has two roundish, or, in one 

 species, conical pimcreatic glands. The ovarium is rolled up like a 

 baU ; contractile vesicles exist in three, and glands in two species ; 

 transverse bands (four to ten) are visible in two species; and a respi- 

 ratorj^ tube, probably, in S. pectinata and S. tremula, a tremulous 

 gill being also present in the fonncr. The principal nervous matter 

 is a laiotty mass surrounding the head of the oesophagus, and in the 

 middle of it is a large, roundish, red eye. In S. pectinata tliree pair 

 of ganglia and strong nerves are also seen. (For remarks on the 

 genus, see Ilydatina, p. 628.) 



S. pectinata. — Body short, conical, with two styles, and two crest- 

 like horns anteriorly. " Are these horns," asks Ehrenberg, '' respi- 

 ratory tubes, as in Polyarthra, and in Annraea}"' The liveliness and 

 uniform ti'ansparcncy of this animalcule render it diificult to dis- 

 tinguish its various organs. The styles arise from the muscle of- the 

 oesophageal head, and appear as if belonging to simple -toothed jaws. 

 Fig. 422 represents a view of this creature (dorsal side), and of its 

 organization. Found amongst Conferva. Length l-120th. 



S. JBaltica. — Body ovate j rotatory clusters and styles, four each ; 

 crest single, sessile. This creature is supposed to occasion phospho- 

 rescent light in the ocean. In two samples of ^^'atcr received by 



