14l> TllK AMEKK'AN MONTHLY [May, 



From what li;is been s^iid. it may rciulily Ik* seen that if M. 

 Tcmpi'rc hail examined more samples, tVom other parts, and 

 strata ot" the deposit, tlie above list would have been greatly ex- 

 tetnletl. .Vav/i-M/a f>crma>^na anil .W. tuacuiata arc not men- 

 tioned, but thev occur in extraordinary abundance, the latter in 

 several verv tine tvpes in parts ot' the deposit. Artinocvc/us 

 fmrklfvi. A. ralfsii, A. (•firrnhi'ri^i'ii-Awd A. <v-rt.v.v//.v are recognized 

 in the Connecticut shore diatoms. Of these A. imrk/cyi is by 

 tar the most abundant. The pseudo-nodule, so easily seen in A. 

 chrcnherorii and in A. crassus and generally in A. ra/fsit\ ap- 

 pears to be absent in tlie majority of valves of A. harklcyi. Al- 

 though this is one of the heaviest of diatoms and appears so dense 

 when mounted in balasm. valves which have never been dried 

 are so transparent in water that their markings can scarcely be 

 seen. This shows some peculiarity of structure in which they 

 (litter from other diatoms. I have latelv found A. harklcyi o{ 

 presiselv similar type to that of the Connecticut shore in material 

 sent me from distant localities. 



Dr. Edwards semis eartii from ditVcrent localities on the New 

 Jersev shore which contains the same Ac/inncyc/us, and mud 

 from a swamp in Melbourne, .\ustralia, has the same associated 

 with Navicula caiiccllata and JI\alodiscus subtilis and H. 

 radiatus. On the Connecticut shore. A'^ canccllata occurs 

 abundantlv in tide pools in the marshes with P. balticuni. and 

 Hyalodiscus is found in deeper and more saline waters. 



In Cunningham's find in a marsh near Mobile river is the 

 same Actinocyclus again, with remarkable specimens of Terp- 

 since musica, which occurs only sparingly on the Connecticut 

 shore. Soundings from near Cuxhaven. North Sea. contain Ac- 

 tinocyclus chrcubcrgii and A. crassus. with abundant Rupo- 

 discus argus and Wiccratimn favus and an occasional Na- 

 vicula maculata, precisely similar to those of New Jersev and to 

 the smaller type from Leete's Island. 



I find in the Morris creek material Actitiocvclus Icnia'ssitnus 

 and Actinoptychus subtilis (\'an Heurck's Diatoms of Bel- 

 gium, plate cxxiv, fig. 7, and plate cxxv, figs. 2 and 3). I 

 find also a form larger than anv of tlie others, which, instead of 

 the small marginal spines, has elevated ridges extending about 

 one-third the distance to the centre of the valve, and which has 

 striation decidedly diflerent from any other. Plate cxiv, fig. 9, 

 shows Trlccratlum brlghtzcellll VV^est, var. irlgona ( Dltyllum 

 trigonuiu Bailey), which I have found at Branford, Conn. Figs. 5 

 and S, showing entire frustules. are imperfect, as the central spines 

 are broken. The Branford forms show longer spines terminating 

 in a knob or ball. 



.Soundings from the oyster beds at Clinton, Conn., show nu- 

 merous minute varieties, many of which are rare. The larger 

 forms are chiefly varieties of Coscinndiscus and of other kinds 

 previouslv mentioned, with Plcuroslgma baltlcum, P. amerlca,^ 



