ART. 15 NEW MARINE MOLLUSKS FROM PANAMA BARTSCH 5 



vertical, axial ribs, of which 13 are present on each of the last two 

 turns. They are almost as broad as the spaces that separate them. 

 In addition to these ribs numerous, very closely spaced incremental 

 lines are present, which appear like slender axial threads. In addi- 

 tion to the axial sculptures the whorls are marked by strongly incised 

 spiral lines, of which four occur between the summit and the suture. 

 The first two near the summit are a little more distantly spaced than 

 the next two. The spaces between these incised lines appear as mod- 

 erately elevated cords, and their junctions with the axial ribs form 

 low, well-rounded nodules, the first set of which is at the angle of the 

 shoulder at the summit, which it renders feebly crenulated. Periph- 

 ery well rounded. Base marked by the continuation of the axial 

 ribs, which become somewhat enfeebled anteriorly, and six incised 

 spiral lines, which are consecutively a little more closely spaced from 

 the posterior to the anterior part of the base. The spaces between 

 these incised lines also form low cords, and their junction with the 

 axial ribs likewise produces well-rounded tubercles. The columella 

 is short and is marked by eight closely approximated moderately 

 strong, low spiral cords. The axial ribs scarcely extend upon the 

 columella. Aperture elongate, decidedly channeled anteriorly, 

 outer lip rather thick, rendered wavy by the spiral cords. The inner 

 lip forms a moderately thick callus, which is reflected over half of 

 the columella and also extends over the parietal wall. The inner 

 lip is provided with three rather strong obliquely slanting folds, of 

 which the posterior is the strongest, and the other two consecutively 

 a little weaker. 



Type.—U.S.l^M. No. 368135, collected by C. D. AUeman on 

 Taboga Island, Panama. It has six whorls remaining, and meas- 

 ures : Length, 14.3 mm. ; diameter, 6 mm. 



Remarhs. — There are several more species in our collection from 

 the west coast belonging to this section of Mitra^ but they appear to 

 be all undescribed. It is possible that Mitra solitaria C. B. Adams 

 may belong in this group. The present form seems to differ from 

 that in having fewer axial ribs. 



RISSOINA ALLEMANI, new species 



Plate 1, Figukb 5 



The shell is rather large. Tlie early whorls are decollated in 

 the type. The first of the remaining postnuclear whorls is angulated 

 halfway between the summit and suture. This angulation is less 

 conspicuous on the next turn and disappears entirely on the follow- 

 ing and succeeding whorls, which are quite well rounded. The first 

 and second turns are appressed at the summit, while the succeeding 

 turns are feebly shouldered, the shoulder there being rendered crenu- 



