238 CONTllIBUTIOXS FROM THK NATIONAL HERBARIUM. 



four more a little lower and alternating, and a ring of smaller but stont spines arnnnd 

 the basal rim, has a massiv*^ and iiniqiu^ aspect to whicli then^ is no analog) in ihr 

 forms here und(T consideration. A very much closer a/Tinily is found in Mclosira. 

 Many members of this genus have a h^vel central area elevated above llie rim l)v a 

 cylindrical or conical liuop or band. In fact this niiglit aliuo.st be said to be charao- 

 teristic of the gi'nus. For exam]>lc, see J/, salurnalia Bnin," where even the flaring 

 upp(T rim of (ho band or hoop, d(>scribed above, is perfectly parallehxl; also M./vrox 

 Schmidt, t* where tlie ring of zcmal proc(^sses is also paraHehnl. If we also remember, 

 we have here to do with small diatoms, I\ cahyilos being 0.0(> to 0.075 mm. and J/. 

 coronaria 0.8:^ nun. in <liameter, w(^ shall see we are w<-ll wilhin the avt^rage size of 

 Melosira. It will perhaps he eventually preferable to conslruct a new g(^nus for these 

 allied forms, especially if other species are found which ivtain the essejitial charac- 

 teristic's of those alrt^ady known; and this would have the advanlage of simplifying 

 sonu'what tlu' ctjmi)l(^x group of forms now in<'liided in Mclosira. Careful attention 

 to the deweription and ilu^ figures of ^f. coronaria, especially to tin- zonal view, will 

 yhuw that it is clearly distinct from the Oamarii or Japan speeimens. 



TyptMulhei:. S. Xaticmal Museum, Xo, 59011(5, from station 2807, Galapagos Islands, 

 April 4, IH88; 812 fatlioms. bottom of Cdobigerina ooze and i-oral mud. 



Melosira febigerii ;Gruu.) Mann. 



Podosira /ebujerii (a-un. in Heve & Orun. Sv. Vet. Akad. Uandl. 17^^: 111). 18S0. 

 Van Heur. Synop. pi 84 J. 22-24- 1881. De Toni, Syll. Alg. 2: 13G2. 1804. 



I see no reason f(»r including this form, nor the others so nanu <1 in the above platc^ of 

 Van Ileurck, in Ww genus Podosira. If that g(^nus is to bt^ defined as it generally is 

 (for full details of whicli see under Pod.^sira in this report), and if Melosira and Pudosira 

 arc to retain any valid marks of distinction, such forms as the above can not br se])^ 

 arated from Melosira. In order to avtjid repetition in this rei)ort, the position of the 

 author in this matter luust be considci'ed in connection with his rt^marks under tlie 

 genus Podosira. 



As both Grunow and De Toni (jbserv(^ in the above citations, ihen^ is some resem- 

 blance hetween this species and the more robust and coars(4y marked P. hormoldes 



(Mont.) Kutz.,(^ a species, by the way, that Montagn(^ rightly renanunl Mclosira hor- 

 moides.d 



Fmmd at station :Ui07, Poring Sea. 



Melosira medusa :N[ann, sp. nov. Plate L, i'TcarjiE 3. 



Valve with border and central area; the latter about four-fifths tlu^ diameter of ilw. 

 valvBj has in its centt^ a low, rugose, Inroad knob or boll, the rest of the art^a beiii"- 

 thinly spotted with irn^gular flecks. The border, one-fifth the radius in width, Ix'gius 

 int(Tna]ly in a row of small, granular, wedge-ishaped markings, from the points of which 

 proceed fme wavy lines to the margin. A circle separates lliis granuhited part of the 

 border from tlie out(^r portion. The latter, three-fourths the width of the entire border, 

 is delicately marked with transverse lini's pro(*eeding from the points of the "-ranular 

 wedges, as above stated, and with fiiiei- hues interspersed between them. The lines 

 sometimes anastomose. 



Diameter of valv(^, 0.078 nun. 



An unnanuHl figure of Schmidt's^ has some resemblance to this si)ecies, though it 

 seems entirely to lack the peculiar circh^ of small beaded triangles withiii the striated 

 border. Schmidt there says, ^'Nach Grove vielhidit eim^ unuTi^ Schah^ von Pt(^i)ha- 

 nopyxis, vielh»iclit y.n einem andern fhnus zu ziehen.'' Neither iif these su<-<M'stions 



''Schmidt, Atlas ?)?. JSO.f. 24-25. 18S*2. 



^Op. cit. jil. 180. f. 2S. 



c^\\i\7.. Pacill 52. pi 29. f. 84. 1844. 



'?M(mt. in d'Orbig. Voy. AnuT. Mcrid. 7: 2. 18r>n. 



•^Schmidt, Atlas pi 202. f. d. 1800. 



