TEE PLANKTON OF EASTERN NOVA SCOTIA WATERS 



11 



SESSIONAL PAPER No. 22a 



adorn its anterior end and seem to indicate additions to the length of the tube. It 

 appears to constitute a considerable element of the food of the oyster in Malpeque bay. 



TiNTiNNOPSis — Stein, 



This differs from the foregoing in having the case beset with foreign material. 

 Two of the species commonly occurring at Canso were easy of diagnosis, viz. : T. cam- 

 panula (Ehrb.) Dad. and T. heroidea Stein (figs. 12 and 13). The dimensions of the 

 average examples were in the former case 150 x 130,a; in the latter 43 x 19/a. But in 

 addition to these, forms similar in their general shape to A, suhulata were very common. 

 T. davidow Daday has a total length of 95^ of which 65ju. belongs to the spine; it is 

 40 wide. The specimen figured (Plate IV., fig. 14) exhibits lines of growth and a fine 

 punctulation of the case, where unconcealed by the foreign material. Another variety 

 measures 45/>t in width and 240;u, in total length, of which 95/x belong to the spine, 

 which is set on obliquely to the case. No rings were observed in this variety, and the 

 punctulation was confined to the spine (Plate IV., fig. 15). T. cylindrica is dis- 

 tinguished by the peculiar form of the aboral end of the case, which lacks the spine of 

 the above, but has' a short handle-like process of irregular outline covered with foreign 

 matter. 



T. lobiancoi (fig. 16), a cylindrical form, test-tube like in shape, (190 x 45;a) 

 may possibly be a variant of Jorgensen's T, subacuta, but no annulations were ob- 

 served. 



CODONELLA. — HaecJcel. 



C. ventricosus (Plate IV., fig. 11) was not uncommon in July. Its form, small 

 dimensions (60 x 42^) and constricted neck sufficiently distinguish it. 



0. lagenula Clap, and Lach. — Common in Malpeque bay, is similar in form, but 

 has no foreign particles adhering to the shell. ^ 



PTYOHOCYLis. — B randt. 



P. urnula (Clap, et Lach.) Brandt is a small form very easily recognized by its 

 hyaline case, which is provided with two annular swellings and a thinner slightly 

 inverted and toothed lip (Plate IV., fig. 19). The example observed approached 

 Jorgensen's var. minor, in its dimensions (96 x T5ja). 



CYTTAROOYLIS — Fol. 



This genus is characterized by a wall formed of two lamellae united by transverse 

 plates. The most abundant form at Canso was C. denticulata (Ehrb.) Eol var. 

 gigantea, Brandt (Plate IV., fig. 18), the tubes of which with their delicate reticular 

 sculpture and toothed orifice were very abundant in the plankton in June and July. The 

 average dimensions of the Canso examples were 470 x TO/i,, but shorter and stouter 

 specimens occurred, approaching the variety typica, in which the length is only three 

 times the breadth. The sculpture ceases as the case narrows to its delicate terminal 

 spine, which is as a rule sharp, but occasionally terminates in a knob. 



ECHINODERM LAB V^. 



Three of these were observed, viz., (1) The Pluteus of Sirongyloceniroius dro- 

 hachiensis in its second stage. In addition to the two pairs of ciliated epaulettes at 

 the base of the post-oral and posterior dorsal processes, there is a posterior ring. The 

 greatest length of the larva, which occurred in the end of June and the beginning of 

 July, is 1.25 mm. (Plate V., fig. 1). At a later date (2) an Ophiopluteus made its 



22a— 2 



