46 Transactions. 



Besides tlie genotype, Murravia exarata is the only other species which 

 may be included in the genus with certainty. TerebratuUna ornata Giebel 

 from the Oligocene of Latdorf, Germany, and Hoesfelt, Belguim (c/. David- 

 son, 1874), agrees in possessing the internal crenulation, but has, according 

 to Davidson's figure, a different type of cardinal process. It also certainly 

 cannot be a TerebratuUna. 



A genus nearly related in shape is Disculina Deslongchamps, 1884, based 

 on Terebratida hemis'phaerica Sowerby. This species is radially costate, and 

 has a flat dorsal valve and a foramen similar to that of Murravia, but there 

 are no internal crenulations in the dorsal valve. 



(4.) On a New Form of Terebratella from New Zealand Waters. 



Plate I, fig. 3. 



A small collection of Brachiopods dredged ofi Cape Colville, Auckland, 

 in 20 fathoms, by Mr. Anderton, of the Portobello Marine Fish-hatchery, 

 and presented through Mr. G. M. Thomson to the Dominion Museum, con- 

 sists of a form closely allied to Terebratella sanguinea (Leach), but presenting 

 some interesting differences. As it is possibly only a local race of that 

 species, and may be linked to it by a series of intermediate forms, I do not 

 propose to burden the literature with a new name, that may prove synony- 

 mous, until collections from other northern localities have dispelled the 

 doubt. 



The collection consists of one adult shell and seven half-grown or still 

 smaller specimens. In shape the adult, which is slightly unsymmetrical, 

 agrees fairly well with moderately elongate examples of T. sanguinea, but 

 the beak is suberect instead of erect, and in consequence the foramen is 

 farther removed from the dorsal umbo and the pseudo-deltidium is higher. 

 The beak-ridges also are less pronounced, and the sinus on the dorsal valve 

 is broader, shallower, and commences more imperceptibly, so that the anterior 

 commissure presents a regular ventrally directed curve instead of a nearly 

 rectilinear angled trough, and the front margin is rounded instead of straight. 

 The most striking difference, however, lies in the almost complete reduction 

 of the radial multicostation. The radial ornament that still exists is irregu- 

 larly distributed on all the specimens, and varies in its distribution in different 

 individuals, in some being more marked on the sides, and in others along 

 the fold and sinus. One shell shows an area corresponding to the middle 

 period of growth in which the ribbing is entirely absent on the sides, although 

 it was present at an earlier stage and appears again at a later stage. The 

 ribbing in no case commences near the umbo, the earliest stage for about 

 5 mm. being completely smooth, but it is much better developed in shells 

 of about 15 mm. than it is in the adult, which measures 31 mm. in length. 



A somewhat analogous case in the same genus is furnished by T. dorsata 

 var. submutica Fischer and Oehlert (1892), in which the shells start with a 

 smooth stage, develop multicostation for a short period, and finally become 

 smooth again before adolescence. 



List of Papers referred to. 



Blochmann, F. (1908). " Zur Systematik imd geographischen Verbreitung 

 der Brachiopoden." Zeitschr. f. wiss. Zool., Bd. 90, pp. 596-641. 



— — (1912). " Die Brachiopoden der Schwedischen Siidpolarexpedition." 

 Wissensch. Ergebn. Schwed. Siidpolar-Exped. 1901-3, Bd. 6, Lief. 7. 



Buckman, S. S. (1907). " Brachiopod Nomenclature : the Genotype of 

 Terebratida." Ann. Mag. Nat. Hist., ser. 7, vol. 9, pp. 525-31. 



