Greenlcaf.] 80 [November 14, 



lished by Prof. Gregory in his papers on Glenshira Sands, in the 

 Quarterly Journal of Microscopical Science, and some of the forms 

 published more recently in the same Journal, by Dr. Greville. 



I have not found any decidedly new species, although I have ex- 

 amined with great care more than twenty slides from the different 

 dredgings. One or two forms are new to me, but I consider them as 

 varieties of species already published. 



And here, let me say, the student in this department of Natural 

 History is sorely perplexed. Many forms published as new species, 

 certainly vary less from those previously figured and described, than 

 many acknowledged as varieties do from the type species. For ex- 

 ample, the varieties of Navicula d'uhjma differ more from the typical 

 form, than many of the fui-ms claimed as new species, do from the 

 original of Navicula d'uhjma. The same difficulty arises in the study 

 of many other genera of these most beautiful of all microscopical 

 objects. 



I hope some earnest student in this department will find time to 

 engage in the most difficult task of reviewing all that has been pub- 

 lished, rejecting all superfluous genera and species, and thus bring 

 order out of great confusion, and make the study of these minute 

 objects comparatively easy. 



The diatoms most abundant on these slides are Navicula lyrOy 

 Triceratium Favus, T. obtusum, Hemidiscus cuneiformis (= Euodia 

 gibha) and small Coscincodiscea. 



Sponge spicules are very abundant and perfect. I recognize many 

 of Ehrenberg's figures. 



Minute calcareous shells, or Forayninifera, are very abundant, but not 

 in great variety. Those particularly noticed are PlanuUna and Rota- 

 lia of Ehrenberg. Polycystina are also abundant, but much broken ; 

 a few forms are quite perfect. 



In all these soundings are found nearly the same forms of each fam- 

 ily. I have only attempted to catalogue the diatoms, not having 

 studied the others enough to verify or name them. 



FROM A DEPTH OF FOUR HUNDRED AND THIRTY-TWO FATHOMS. 



Triceratium Favus. Eupodiscus punctulatus. 



" obtusum. Navicula praetexta. 



" unguiculatum Grev. " lyra. 



" spinosum Bail. " clavata. 



" venulosum Grev. Navicula Smithii. 



Biddulphia sp. Pleurosigma sp. 



Campylodiscus Kutzingii ? Bail. Cocconeis pseudomarginata. 

 Nitzschia panduriformis. " distans. 



