38 THE VOYAGE OF H.M.S. CHALLENGER. 



intercalation of shorter ribs. The surface is also crossed at intervals by fine concentric 

 lines of growth. In the interior of dorsal valve the loop is simple and short, and 

 rendered annular by the union of oral processes. Shell structure perforated by canals. 

 Brachial appendages united by a membrane and divided into three lobes, the shorter 

 central one is spirally coiled. Length 38, width 25, depth 22 mm. 



Habitat. — Ter. cancellata was dredged abundantly by the Challenger Expedition on 

 April 2, 1874. Station 162, off East Moncoeur Island, Bass' Strait, in a depth of 38 

 to 40 fathoms ; sea bottom, sand. Mr Dall states that it occurs oS West Australia. 

 This Terehratulina attaches its peduncle chiefly to different species of moUusca, such 

 as Pecten, Cardium, Area, &c. ; to several species of univalves, spines of Cidaris, 

 stones, &c. 



Observations. — This fine species strikingly recalls some specimens of the Cretaceous 

 Terebratulina defrancii, as some Mediterranean examples of the recent Terehratidina 

 caput-serpentis, the Cretaceous Ter. striata. When young, Ter. cancellata is longitudinally 

 spindle-shaped and oval, but aged examples show more of a straight front. Some of the 

 specimens dredged by the Challenger Expedition have much exceeded in size, those 

 figured by Koch, in Kiister, by G. B. Sowerby, and L. Reeve. Its colour is also peculiar, 

 being darker than the other species of recent Terebratulina, and more especially so in 

 some specimens than in others. There exists likewise in some exceptional specimens a 

 median depression in the anterior portion of the smaller valve, commencing at about 

 the middle of the valve and extending to the front. 



Terebratula or Terebrattdina (?) dalli, n. sp. (PL II. fig. 15, a). 



Shell small, thin, longitudinally oval, globose, glassy, and semitransparent, slightly 

 depressed anteriorly. Ventral valve uniformly convex, a little deeper than the dorsal 

 one. Beak small, slightly incurved, and truncated by an incomplete foramen, laterally 

 margined by a small deltidial plate. Surface covered with fine radiating raised strise, 

 with shorter ones interpolated between some of the larger ones at various distances from 

 the beak. Loop short and simple. Length 8, width 5-|, depth 4 mm. 



Habitat. — One example only of this species, without the animal, was dredged by the 

 Challenger Expedition near Yeddo, off Japan, at Station 237. June 17, 1875. Lat. 34° 

 37' W., long. 140° 32' E. Depth, 1875 fathoms. Bottom temperature, l°-7 C. Mud. 

 Associated with Discina atlantica. 



Observations. — I regret that but one dead sjjecimen of this very pretty little s]3ecies 

 should have been obtained, the loop was imperfect, but it seems to have been short as in 

 Terebratula or Terebrattdina. The striae which cover the shell surface are distinctly 

 observable, both valves are, likewise, very convex. I am not acquainted with any recent 

 form with which it can be assimilated. I have much pleasure in naming this small and 

 interesting species after Mr W. H. Dall of the United Coast Survey, whose ably conducted 



