82 



Hab. Five miles east of Ruapuke Island, New Zealand ; dredged 

 by Mr. Evans, R.N., in 19 fathoms off coral and rock. Coll. Cu- 

 ming. 



Obs. — When Sowerby described this interesting shell, only one 

 small young specimen, without locality, was known ; since then Mr. 

 Evans has dredged several, some of which exceeded the dimensions 

 above given. I therefore thought it advisable to redescribe and figure 

 the species ; more especially, as it is scarcely distinguishable from 

 half-grown specimens of R. concinna, Sow. 



12. Orbicula Evansii, Dav. 1852. (PI. XIV. fig. 32-34.) 



Diagnosis. — Shell irregularly circular, nearly as wide as long, very 

 thick ; both valves almost equally orbicular or suborbicular ; apex 

 subcentral ; the unattached valve is ornamented by numerous strong, 

 radiating, elevated strise, which augment rapidly by the intercalation 

 of numerous smaller costee at variable distances from the apex ; these 

 are intersected by numerous concentric laminae of growth ; attached 

 valve very deep ; disk of adhesion small, almost central ; fissure mi- 

 nute, elongated ; surface covered by concentric raised laminae, with 

 longitudinal striae all round and near the edge ; colour yellow ; texture 

 horny. Length 5^, width 6, depth 4 lines. 



Hab. Bodegas. Coll. Cuming. 



Obs. — Mr. Cuming has three specimens of this Orbicula, all similar 

 in appearance, and distinguishable from O. Cumingii and O. strigata 

 by the great convexity of the attached valve, which is flat in the two 

 above-mentioned species ; the disk of adhesion is likewise much 

 smaller in O. Evansii, and the striation stronger. 



EXPLANATION OF THE PLATE. 



Fig. 1, 2. Terebratula Grayii, Dav. ; natural size. 



Fig. 3. Terebratula Grayii, Dav. ; interior of smaller valve. 



Fig. 4, 5. Terebratella Bouchardii, Dav. ; natural size. 



Fig. 6. Terebratella Bouchardii, Dav. ; interior of smaller valve. 



Fig. 7. Terebratella Evansii, Dav. ; enlarged. 



Fig. 8, 9. Terebratella Evatisii, Dav. ; interior of smaller valve. 



Fig. 10-12. Terebratella ? Cumingii, Dav. ; enlarged. 



Fig. 13. Terebratella Cumingii, Dav. ; back of the beak, showing the foramen. 



Fig. 14. Terebratella Cumingii, Dav. ; interior of smaller valve. 



Fig. 15. Terebratella Cumingii, T)aN.; sectionoftheinteriorof both valves, showing 



the position of the septum. 

 Fig. 16. Terebratella Cumingii, Dav. ; interior of smaller valve, much enlarged, 



showing the fringed arms ; A, A, the cardinal muscles ; B, the adductor 



ones ; C, the pedicle muscles. 

 Fig. 17-19. Terebratulina Cumingii, Dav. ; enlarged. 

 Fig. 20, 21. Kraussia Deshayesii, Dav. ; enlarged. 

 Fig. 22, 23. Kraussia LamarcJciana, Dav. ; enlarged. 

 Fig. 24. Argiope Neapolitana, Scacchi; enlarged. 

 Fig. 25. Argiope Neapolitana, Scacchi ; showing the two-lobed loop. 

 Fig. 26. Argiope decollata, Chem. ; interior of smaller valve, enlarged to show 



the four-lobed disposition of the loop. 

 Fig. 27. Argiope cuneata, Risso ; greatly enlarged, showing the interior as seen 



in the dried specimens: D, the mouth, fringed arms and two-lobed 



