4()0 ALBATROSS PTEROPODS AND HETEROPODS — PECK. 



side view of lon(/irofitrif< (/>) sliows also t lie great drvolopinent of llio 

 dorsal (lower in the tigiire) lij* of the sUcll, i>roloug-ed into the louj;- 

 hood which runs far out beneath the overlyiiiji' fins, and sculptured 

 with the (h'ep nolch in its anterior part. This little shell is, in many 

 respects, the most highly developed, as it is also the most abundant in 

 thecoUections. 



('. f/ihhosa — Fii>-. 4, <( ventral, h lateral view — is characterized b\' the 

 promintMit transverse keel into whi»'h tlu^ anterior surface of the \cntral 

 li|> is di'veloped. This fcatnre appears in lateral view, Fig. I h, and is 

 evidently dne to an accelerated growth of the shell in this pai't, as is 

 shown by the strong ridges and width between the lines of deposit, giv- 

 ing it a markcdI.N serrated contonr at this ])oint. The dorsal (lower in 

 the drawing) lip of this species is also relatively large at its ant«'rior 

 part, torming a deep hood nnderncitii the tins. On these accounts the 

 posterior asjx'ct (»f gibbosa is comparatively narrower llian the anterior 

 part (see a of l^'ig. 4) which is one of the points nscd in giving it its 

 systematic position. 



Figf. 5 shows in outline a representative of the species tridtntala; a 

 from ventral, h from lateral view. All the mend)ei's (»f this species taken 

 on this tri[) of the Alhafross were (piite large, and the one tignicd was 

 one of the largest specimens; they were not \('ry abnndant. It might 

 well be chosen as a tyi)ical Cavolinian ])tcropod shell; m)ne of th«' parts 

 arc exaggerated, all are synnnetrically deN eloped. The lateial \ icw //, 

 however, imperfectly represents the measure of the dorsal lip of the 

 shell, the anterior hoodliko ])roJection of which was broken ott' in the 

 specimen lignred ; in a complete specimen it is mori' nearly like the sanu^ 

 structure in ('. (jibbosd (l^'ig. 4 />), although not quite so well develoi)e(l. 



The two specimens of ('(/r«>//></r< which have the ])OSterior and lateral 

 pai'ts of the shell drawn ont into points (but with tlu'ir anterior margin 

 of dorsal lijt) an^ uncinata and hijlcva. The former of these is repre- 

 sented in Fig. ."> in a dorsal and h lateral view. The posterior spine of 

 tlu^ shell is relatively quite long and strongly curved backwards, whih^ 

 the lateral ])oiuts of the shell give a considerable increase to the expanse 

 of the aperture between the two lips. The dorsal lip also is very 

 strongly <'urved and compressed antero-i)Osteriorly, while the ventral 

 lip is very nuwh rounded, showing upon its anterior face the lines of 

 growth of the shell deposit. I^'inally, I'ig. 7 represt'uts the form of Caro- 

 Unin iuflcxd, (( fnnn \entral, and h from lateral view. Tlie slicU is nun-h 

 more tnbnlar than that ol' ini<-iii<i(<t, the lateral ])oints gixing witltli to 

 the apertnre of the shell, wiiich does not, howcNcr, extend the whole 

 length of t lie shell, t lins leaving a very long" curved posterior i)art. The 

 dorsal lip, moreover, runs straight forward and does not curve nj) into 

 a hood below the lins, as is m(n'e or less the case in the other s[»ecies. 



Sncli are the relations of these species as indicated in Figs. 1-7. 

 In every case the anterior of the diawings of the shells is t(»ward the 

 right (except the front view in Fig. Ic) and the ventral face of the shell 



