OF THE VOLVOCINA. 



519 



within a crystalline envelope. In stag- The number of animalcules in the tablets 



nant water. Corpuscles 1-3000" ; tablet varies from four to sixty-four. In sea- 



of 20 to 25, 1-600" in breadth. water. Size 1-5000" ; tablet 1-500" in 



G. f/lancum. — Corpuscles bluish- diameter, 

 green, within a crystalline envelope. 



Gonium tmnquUhim and G. glaucum, says Perty, are Algae (/. e. he would 

 say, are not members of this genus). He adds as a new species, 



G. helvetieum. — The green, spherical 

 corpuscles combined in a tabular, gela- 

 tinous envelope, without any intercom- 

 mmiicating bands, each furnished with 

 a fine red stig-ma and two ciliary loco- 

 motive filaments. On a polar view, one 

 large roimd vesicle is -visible ; on the 

 lateral aspect, two such are apparent, 

 one larger than the other. On drying 



the specimen, the stigma itself assumes 

 the fomi of a vesicle. It is readily dis- 

 tinguished from G. quaclrcmgulatam by 

 the absence of the connecting bands or 

 tubules between the several corpuscles 

 in the tablet. Diameter of tablet 1-360", 

 of coi'puscles 1-1300". Filaments 2^ 

 times longer than the gonidia. In ponds 

 about Bern. 



Genus SYNCRYPTA (XX. 26-28).— This genus is mainly characterized 

 by secreting or hiding itself (as the name implies) within a second envelope. 

 Each individual is provided with a special lorica of the form of a little shield 

 (scuteUum), and is united with others m a common gelatinous envelope (la- 

 ceriui) into which it can retreat ; neither eye-speck nor tail is present, but 

 there is a large filament ; self- division longitudinal. The filaments of the 

 several corpuscles give the cluster an appearance of being surrounded with 

 hairs. 



With this genus Dujardin would identify his Cryptomonas (Tetrahcena). 

 The very doubtful position and independence of tliis genus as a member of 

 the Yolvocina have been remarked on in the general notes on this family 

 (p. 144). Mr. Carter, iii a paper lately published (A. N. H., 1859, iii. p. 1 et 

 seq.), represents Sijncry]pta to be the " spermatic form " of Volvox or of Sj^hce- 

 rosira (Ehr.). (See notes on Sph^eoslra.) 



This berry-like cluster of animalcules, 

 when rolling through the water, is a 

 beautiful object for the microscope; and 

 with the aid of a little indigo, the nu- 

 merous currents it creates are readily 

 perceived : xx. 27. magnified 260 dia 

 meters ; fig. 26. 400 ; an(^ 

 about to sever into four, 



fig. 28 a cluster 



SiTNCRYPTA tolvox (xx. 26-28). — 

 Form oval ; colom* green, with w^hitish 

 rays in the centre. Generally in water 

 drained fi'om Confervae. 1-2880"; a clus- 

 tered globule in its crystalline tunic, 

 hardly exceeding 1-570". Fresenius 

 states that he has seen a red stigma in 

 each corpuscle, which was overlooked by 

 Ehrenberg. 



Genus SYNUHA (XX. 29, 30). — Eye-speck absent ; tail filiform, attached 

 either to the base of its own lorica or to the centre of the cluster to which it 

 belongs. The general envelope is spherical, gelatinous, and is hollowed out 

 by as many compartments or cells as there are individuals in the little com- 

 munity. From out of these cells they can stretch themselves a considerable 

 distance, whilst they continue attached by the extremely delicate and exten- 

 sible tan. This so-caUed tail or pedicle is homologous with the connecting 

 rays or threads of the several corpuscles in the globe of Volvocc, and is, like 

 them, a production of the protoplasm of the interior. As before remarked, 

 this genus is doubtfully retained ; for the chief distinctive feature Ehrenberg 

 insists on, viz. the presence of a double lorica, loses its significance now that 

 modem researches have shown that the formation of a second or common en- 

 velope is an ordinary phenomenon at a certain stage of existence of most or 

 of aU A^olvocina. Moreover, the description given of this genus is too loose 

 and faulty, and its accompanying illustrations too rude, to render it possible 



