46 G. LINDSTRÖM, ON TIIH SILVMUAN GASTUOPOIJA AND l'TEUorODA OF GOTLAND. 



size. The section of the aperture is rectaiigular with tlie coniurs roundcd and a littlc 

 bent in by the grooves. The substance of the shell is extremely thin, quite as uiuch 

 as in the folloAving species, and seems to consist only of a single stratum, which has a 

 chcstnut brown colour. The outer surface is very finely striated by arched, almost 

 microscopically minute, transverse lines. They form a gentle cnrve, highest at the 

 median, longitudinal axis of the face and lowest at the corners, where they again are 

 slightly bent iipwards. They are so crowded as to be about 26 within a length of 2 

 millim. from the midst of the shell and upwards (fig. 7), biit lower down, near the 

 apex, the}' are more apart (fig. 6), that the interstitial furrows there are nearly 

 thrice as large as the elevated lines. When these transverse lines are examined with 

 high magnifying powers they are seen to be covered with closely set, elongated, oval 

 tubercles (fig. 8), protracted into acuminated apices above and below. The interstitial 

 furrows are quite smooth and glossy. What is most remarkable in this species is the 

 presence of two longitudinal septa on the interiör surface of each face. They are seen 

 on the outside through the transparent shell, as two black longitudinal lines, which 

 continue slightly diverging from each other, being one millim. distant near the apex 

 and 3 millim. near the aperture, always on both sides of the median axis of the face. 

 They project a little inward in the cavity of the shell, as seen in fig. 5 and they 

 correspond evidently with the single ridge of which there is a faint trace in Conularia 

 monile and are probably also homologous to the longitudinal septum of the recent 

 Styliola. — Height 40 millira., breadth at aperture 32 millim., shorter diam. of same 

 28 millim., diagonal 35 millim,, breadth at apex 5 millim. Hitherto only one specimen 

 has been found in the shale beds at Länsa in Fårö. 



5. Conularia aspersa n. 



Pl. VII figs 1—3; pl. XIX fig. 1. 



Shell tapering, conical, probably regularly pyramidal, but this cannot be ascer- 

 tained as the extreme thinness of its substance has caused that it has been preserved 

 only in compressed and wrinkled specimens and consequentl}' the outlines of only one 

 face is laid in view, when the soft, marly limestone in which it is enclosed, is split open. 

 Although the thin shell is bent in many creases and wrinkles, its delicately ornamented 

 surface is beautifully clear and distinct. Along the median axis of each face there 

 run two straight, nearly parallel septa, visible on the outside as dark narrow lines. 

 There are absolutely no ingoing folds on the exteriör surface, where they are situated, 

 what is so common in other species except the preceding one. They slightly deviate 

 in their course upwards and are nearly two millimeters apart near the aperture. The 

 transverse rows of the ornamental tubercles are more closely set than in the preceding, 

 nearly related species. They number as many as 14 along a longitudinal line of one 

 millim. Being so close, they with their tiny tubercles give the surface a chagreened 

 appearance. The tubercles are nearly circular knobs with the interstices confusedly 

 streaky. The colour is dark brown or chestnut. 



