INVERTEBRATAj CRYPTOGAMIAj MICROSCOPY, ETC, 



937 



tylopora, &c. In the fossil forms a calcareous skeleton remains, very 

 liable to be confounded with that of foraminifera, in which are hollow 

 chambers and canals, where the fructification and the rays have been 

 and by means of which they may be determined with great ease. 



The author thus classifies the genera belonging to the group. 

 Those marked thus * are fossil genera ; those marked * * are known 

 in both the fossil and living state : — 



I. Cymopolidse 



II. Acetabularidse .. 



III. Thyrsoporellidas 



IV. DactyloporidiB .. 



V. Neomeridoe 



VI. Uteridae 

 VII. Hagenraulleridse 



Dasycladus. 



Halicoryne. [ 



Clypeina.* I 



Cymopolia.** j 



Parkerella.* I 



Hermitella.* 



Polyphysa. 



Acefabularia. 



Acicularia.* 



Briardiiia.* 



Oriojiovella.* 



Thyrsoporella.* 



Gumbeliiia.* 



Dactylopora.* 



Neomeris. 



Bonietolla.* 



Terqiieiuella.* 



Maupnsina.* 



Zittelina.* 



Uteria.* 



Hiigenmulleria.'' 



Carpenterella.* 



A. Decaisnella.** 



B. Larvaria.* 



C. Vaginopora.* 



D. Karreria.* 



E. Polytrypa.** 



Influence of Light on the Movements of Desmids.*— According 

 to Stahl, when Closterium is placed in a vessel which the light reaches 

 only from one side, the cells attach themselves to the glass in such 

 a position that the longer axis of the cell coincides with the direction 

 of the incident light. If the direction of the light is altered, the 

 position of the cell varies correspondingly with more or less rapidity. 

 There appears, therefore, to be a certain difference between the two 

 halves of the cells in respect to their behaviour towards light, one 

 extremity seeking and the other avoiding it. It is remarkable that 

 in this respect the properties of the two halves seem to alternate from 

 time to time, causing a change in the direction of the longer axis to 

 the extent of 180°. Intense light appears to have a very different eff"ect 

 on desmids to that of diffused light, the cells then placing themselves 

 in a position in which the longer axis is at right angles to the direc- 

 tion of the incident light. 



New Diatom, t — A new genus and si>ecies of diatom from the Santa 

 Monica deposit is described by Mr. Stodder ; the following are given 

 as the generic and specific characters : — 



" Discus (a plate), n. g. It is a simple disk, translucent like 



* ' Verb. Pbys.-mod. Gesellsch. Wiirzburg,' xiv. No. 7 ; sue ' Hedwigia,' xviii. 

 1879, p. 100. 



t 'Am. Jouru. Micr.,' iv. (1879) No. 3. 



