54 PROCEEDINGS OF THE MALACOLOGICAL SOCIETY. 



Inner lip spread on the body-whorl. Columella straight. Base but 

 slightly convex, with a subangularity below the lowest ridge. 



Length of a medium-sized specimen 19 mm., width 6-5 mm. The 

 depth of the sinus unknown, none of the examples being entire. 



Two dead shells were obtained in Bass Strait at a depth of 

 45 fms. in coarse sand and dead shells. Two specimens in my own 

 collection are from Tasmania and Port Jackson respectively. They 

 were procured from Mr. Sowerby, who has three other examples. 

 In the British Museum there is also another individual presented by 

 Mr. J. H. Ponsonby from Diana's Basin. 



This differs from other species of the section Colpospira in having 

 a much broader and shallower sinus ; it, however, agrees with them 

 in the general character of the shell and the form of the aperture, 

 more especially with Turritella sinuata, with which it has hitherto 

 been confounded. The columella, as in that species, is even more 

 nearly straight than in most of the species of Colpospira described, 

 and it has not the twist backward of Turritella runcinata and 

 T. accisa. In spite of the difference in the form of the sinus it 

 appears advisable at present to place it in this section until we 

 obtain some knowledge of the animal and learn whether any 

 special structural characters are associated with the variation in 

 the dimensions of the sinus. Should it prove to have distinctive 

 features, Platycolpus would be a suitable name for a section of 

 which it would be the type. Turritella quadrata is distinguished 

 from T. sinuata, not only by its broader and shallower sinus, but 

 also by its stronger ridges, the spiral threads not being so coarse 

 comparatively as those on T. sinuata, and by their being differently 

 disposed, and by the colour-markings being broader. Two specimens 

 in the British Museum (Natural History) marked 906, referred to by 

 the Rev. R. Boog Watson as similar to but distinct from C. runcinata, 

 appear to belong to this species. They are larger, and are evidently 

 dead shells, since the colour is much faded. The largest consists of 

 thirteen whorls, and has a length of 24 mm. 



5. Turritella (Colpospira ?) quadrata, var. scitula, n. 

 PI. V, Figs. 9-9«. 



This seems to be a well-marked variety of Turritella quadrata, 

 having more prominent ridges, and the space between rather more 

 concave. 



I have one specimen in my collection from Port Jackson. It 

 consists of fourteen whorls, and has a length of 18-5 mm., width 6 mm. 

 In the British Museum (Natural History) there is another individual, 

 No. 87, dredged by H.M.S. "Challenger" off the same locality, at 

 a depth of 30-35 fms. It is larger, and the spiral angle is greater, 

 being more like that of the type of C. quadrata; it possesses twelve 

 whorls in a length of 2 1 mm. 



For assistance in preparing this paper I am greatly indebted to 

 Mr. E. A. Smith, who has not only been most obliging in giving me 

 every facility for studying the shells under his care, but also in 



