BY G. I. PLAYFAIR. 



471 



should it be thought necessary to embody a system of classifica- 

 cation in the name of any organism? I have, therefore, made 

 every distinct form a variation of the type holding priority. 



Subspecies Ehrenhergii is only the forma minor or, as only 

 breadth counts in these long forms, the forma gracilior of trahe- 

 cida proper. Disregarding what may be termed infantile forms, 

 the breadth in this group ranges from 18^ to 37//, while in 

 trabecula proper the range is from 37/i to 76/x. 



Doc. TKABECULA var. EHRENBEGIl(Breb.). 



Long.264-608; lat. bas.18-28; centr. 17-25; ap.12-18/^, 

 Ubique. 



The sizes include f. minor and var. elongatiim. (See note,. 

 supra, on Delponte's Ehrenhergii). 



Var. CONSTRICTUM, n.var. (Pl.xi., f.ll). 



Forma var. Ehrenhergii proxima, cylindracea, apices versus 

 levissime attenuata; lateribus parallelis; apicibus subtruncatis; 

 supra inflatione basali valde constricta et sursum leviter 

 excavata et infiata (ad haculum ace), lateribus in excava- 

 tione undulatis. Membrana vulgo dilute scrobiculata. Long. 

 644-606; lat. bas.26-28; centr.24-25; ap.l8/x. 



Prospect(43), Coogee(l). 



The only differences between this form and var. Ehrenhergii 

 are the decided constriction, and curious excavated appearance 

 above the basal inflation, in which lie one or two lesser undula- 

 tions. The shape is somewhat like Doc. 6ac?t^Mm(compare Pl.xi., 

 f.l4). This form is intermediate between var. Ehrenhergii and 

 var. Delpontei; the excavated appearance is, I consider, caused 

 by the swelling of the cell above the basal u-ndulations prepara- 

 tory to a widening of the isthmus. The base is somewhat like 

 that of PL Georgicum Lagerh., Amerikas, f.29, but the semicell 

 hardly at all inflated. 



Var. Delpontei mihi. PI, Ehrenhergii Delp., T.xx., f.1-7. 



Forma inter var. Ehrenhergii et traheculam var. crenulatum 

 intermedia. Semicellulse cylindracese, basi levissime inflatse et 



