292 J\Ir. C. Mereschkowsky on Californian Diatoms. 



XXXIX. — A List of Californian Diatoms. 

 By C. Mereschkowsky. 



[Plates lY. & v.] 



The recent marine Diatoms of California are interesting in 

 more than one respect. In the first place a list of Californian 

 Diatoms will form a desirable contribution to our knowledge 

 of the geogTaphical distribution of these little Algaj, the more 

 so as the Diatom flora of the Pacific is as yet but very little 

 known. Then, again, tlie study of recent Californian Diatoms 

 as compared with the extensive fossil deposits of this region 

 is of interest in order to ascertain which of the fossil forms 

 have disappeared and which are still living, and whether tliese 

 latter have changed in the course of time or not. 



It is for these reasons that I undertook the study of Cali- 

 fornian Diatoms, which I intend to carry out as completely as 

 possible — a task which will certainly require a number of 

 years in order to accomplish it with a certain degree of com- 

 pleteness. At the present time I will only give a short 

 preliminary list, partly composed of forms observed by myself 

 so far as I have been able to determine them, partly of some 

 species which have been previously noticed by other diatomists, 

 especially by Cleve in his ' Synopsis of the Naviculoid 

 Diatoms,' as well as by a few others (Grunow, Greville). 

 This list will also contain the species which I have already 

 mentioned and partly described in a previous publication 

 entitled 'On Polynesian Diatoms,' the fourth chapter of which 

 deals with Diatoms belonging to the Californian coast. 



The reader will find in this paper the description of a 

 number of new species and varieties, accompanied by 

 figures. Some of them are small and delicate forms which 

 I have observed in a living state or in preserved crude 

 material, and which can hardly be expected to be found in 

 slides, as such forms usually completely disappear during 

 the cleaning of the material. Certain details of their structure 

 (such as the strise when very fine) could not, for this reason, 

 be ascertained. 



In the list I indicate the person who has observed the 

 species by the first letter of his name — C. meaning Cleve, 

 G. Grunow, Gv. Greville, and M. myself. 



1. Diploneis bombus, var. bullata, CI. [C] 



2. Diploneis bombus, var. densestriata^ CI. [C] 



3. Diploneis contigua;, var. eudoxia_, A. S. [C] 



