230 Messrs. W. K. Parker, T. R. Jones, andH. B. Brady on 



XIII. Nautilus (0.) Pennatula. The Sea-feather Sea-stafF. PL 4. 

 figs. 13 «— 13 c. [Grammostomum Pennatula, Batsch.] 



(Trqms.) " The partition- walls, which at the beginning of its growth 

 are strangely crowded together, make at the upper* end of the 

 shell an altered feather-like portion. Figure e represents one of 

 these parts alone." 



We have here five beautiful figures of the wide, flat Textula- 

 rian form which commonly becomes uniserial in its mature 

 growth. The subgeneric term Grammostomum is employed for 

 this group. D^Orbigny (Modeles, No. 59) represents the same 

 varietal form under the name Vulvulina capreolus, 



XIV. Nautilus (0.) Harpa. The Harp-shaped Flat Sea-staff. 

 PI. 5. figs. 14«-14e. [Fig- 14 «. Frondicularia complanata, 

 Defrance (fragment) ; fig. 14 5, c. Flabellina Harpa, Batsch j 

 fig. 14td,e. Planularia Auris, Fichtel & Moll.] 



(Trans.) "The shell is quite flat, bright, and smooth. The parti- 

 tion-walls run obliquely, are parallel, and shine through the other- 

 wise opaque shell. In this and in figure 13 may be clearly seen 

 how little nature has made the evident character depend upon 

 either form or colour." 



The five fine drawings on this plate are a somewhat mixed lot 

 of closely allied forms. It would scarcely be right to supplant 

 Defrance's name for the subtypical Frondicularia on the autho- 

 rity of a figure of a fragment of shell confused with other speci- 

 mens. Figs, b and c constitute the first notice we have of the 

 Flabelline character of growth ; and BatscVs trivial name falls 

 naturally into its place for the smooth partially costate forms. 

 The other two figures represent Planularia Auris, F. & M. 



XV. Nautilus {Lituus) arietinus. The Ram's-horn Bishop-staff. 

 PI. 6. figs. 15 ff-15 /. [Fig. 15 fl, b. Peneroplis pertusus, For- 

 skal; fig. 15 c. Peneroplis pertusus, var. arietinus, Batsch; 

 fig. 15 d, e, f. Spirolina Hemprichii, Ehrenberg.] 



(Trans.) *' In all the different forms two characters remain quite 

 evident, namely, the strong shell and its numerous folds or wrin- 

 kles. It is also much coiled." 



The varieties of Peneroplis of which this plate consists are, 

 with much judgment, separated generically from the forms pre- 

 ceding them, which, as we have shown, belong almost entirely 

 to the Nodosarian group. The term Lituus used by our author 

 had previously been employed by Gmelin as a specific name for 

 one of the varieties of the genus; consequently it cannot be 

 brought forward to displace the well-known and convenient 

 generic appellation originated by Montfort, Peneroplis, 



* Really the lower or first-formed portion. 



