KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 19. N:0 4. 123 



4. Var. agglutinans d'Orb. We rettiin tliis name, notwithstandins^ it is not pro- 

 perly applied in a group of forms through which this feature is so coinmonly distri- 

 buted. It comes near to the typical form, but its ajjertiire heing furnished with margi- 

 nal teeth — which feature seems to be of some constancy — there is a reason for 

 ranking it as a distinct variety. The tongue of the mouth is generally forked. It is 

 finely agglutinant (h. e. composed of finest chalkdebris) and attains on the chalk-bot- 

 tom a larger size than any other of these varieties. 



5. Var. pulcheUa d'Orb. On the experienced authority of Mr. Brady we refer 

 to this variety all longitudinally plicated forms of Mil. seminulum. It raay be, that 

 the designation of >^bicomisi) Walk., should have the preference as cider. Our form is 

 not a typical imlchella, but irregularly and scantely plicated, generally longnecked 

 and a little agglutinant. It is found very rarely in coralline-gravel. 



6. Var. Brogniartii d'Orb. A finestriated Mil. seminulum, usually of the same 

 shape as Mil. oblonga Mont. 



It would, no doubt, be more conformable to a natural arangement of the va- 

 rieties of this species to assign to the striated and ribbed forms a place under their 

 respective correspondiug smooth forms; for it seems as if those varieties had origi- 

 nated directly from each of the principal smooth ones. Nevertheless we have provi- 

 sionnally brought together in our synoptical list of synonyms all striate and costate 

 forms under one head. 



Figg. 319 — 320: the typical or nearly typical Mil- seminulum somewhat aggluti- 

 nant; from the chalk-bottom. 



Figg. 321 — 329: pigmyforms and young of Mil. seminulum; from 0,07 to 0,20 

 mm. in length. 



Figg. 330 — 334: var. sca/^Aa d'Orb.; 330: endview; 331: edgeview; 332: sideview; 

 the aperture resembling that of Mil. ringens; 333 — 334: transverse and longitudinal 

 sections of the same. 



Figg. 335 — 345: transitional forms to flat >'inan^wto?'is» form (porcellaneous); from 

 chalk-ooze. 



Figg. 346 — 354: carinate forms of ntriangularisfi d'Orb.; slightly agglutinant, not 

 quite porcellaneous; from the coralline-gravel. 



Fig. 355: transverse section oi »trigonula^, highly magnified; of porcellaneous lustre; 

 from the coralline-gravel. 



Figg. 356 — 358, tab. X: ^)'pidchellay> with few and irregular folds, slightly agglu- 

 tinant; from the coralline-gravel. 



Figg. 359 — 360: the typical imgglutinansr, d'Orb.; 360 shows the closely toothed 

 mouthedge and the produced forked tongue. 



